Download The aetiology and management of Castleman disease at 50 years

review
The aetiology and management of Castleman disease at
50 years: translating pathophysiology to patient care
Corey Casper
Department of Medicine, Division of Infectious Disease, University of Washington School of Medicine, and The Program in Infectious
Disease, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
Summary
Fifty years ago, Dr Benjamin Castleman first described the
unusual lymphoproliferative disorder that now bears his name.
Over the subsequent decades, astute clinical and pathologic
observations coupled with clever molecular biologic research
have increased our understanding of the aetiology of Castleman disease (CD). This article proposes three broad CD
variants based on both distinctive histopathology and clinical
behaviour. The pivotal roles of infection with human herpesvirus 8 and interleukin-6 production in the development of
CD are emphasized. Finally, the natural history of CD and the
myriad of therapeutic options are reviewed in the context of a
unified model of CD pathophysiology, and continued areas of
uncertainty are discussed.
Keywords: lymphoproliferative disease, Castleman disease,
angiofollicular lymph node hyperplasia, human herpesvirus 8.
Fifty years ago, Dr Benjamin Castleman, a pathologist at
Massachusetts General Hospital, first described a rare lymphoproliferative disorder that now bears his name. Also known as
angiofollicular or giant lymph node hyperplasia, the clinical
manifestations of Castleman disease (CD) are heterogeneous,
ranging from asymptomatic discrete lymphadenopathy to
recurrent episodes of diffuse lymphadenopathy with severe
systemic symptoms. The population prevalence of CD has not
been established; based on the proportion of patients presenting to a large cancer centre with lymphadenopathy of
undetermined origin later diagnosed with CD, it was estimated
that the number of cases in the US ranges from 30 000 to
100 000 (Moore et al, 1996a). The infrequency with which CD
is diagnosed has precluded comprehensive clinical studies,
leading to an incomplete understanding of the disease. Current
knowledge is based largely on case series and histopathologic
reviews. Over the last decade, a large body of evidence has
Correspondence: Corey Casper, University of Washington Virology
Research Clinic, 600 Broadway, Suite 400, Seattle, WA 98122, USA.
supported the importance of infection with human herpesvirus
8 (HHV-8 or Kaposi sarcoma (KS)-associated herpesvirus) in
the aetiology and management of CD. This article provides an
overview of CD and its variants, proposing a classification
system based on both histopathology and clinical findings.
Furthermore, recent advances in the pathogenesis, natural
history and treatment are summarized, emphasizing the role of
HHV-8 infection.
Classification
Dr Castleman initially described a patient who presented with
many years of fever and weakness, and was eventually found to
have a large mediastinal mass at fluoroscopy. Medical evaluation revealed mediastinal lymphadenopathy, which, upon
surgical excision, was found to have strikingly abnormal
architecture of the affected lymph nodes that have come to
characterize CD (Castleman & Thowne, 1954). One dozen
additional patients who were largely asymptomatic but had
mediastinal masses detected in the course of other medical
procedures were subsequently identified (Castleman et al,
1956). The lymph nodes from these patients showed disarray
in all compartments. Most striking were the lymphoid follicles,
both markedly increased in number and unique in morphology. The germinal centres varied in their cellularity, ranging
from a mostly acellular fibrinous hyalinization of capillaries to
proliferations of pale eosinophilic cells with copious cytoplasm. The germinal centre was frequently surrounded by a
marginal zone of concentrical lymphocytes. Increased vascularization was noted in the interfollicular space, with vessels
traversing between multiple germinal centres. Finally, sinuses
rarely appeared in affected lymph nodes. All the initial patients
were only mildly symptomatic, if symptomatic at all, and
surgical resection resulted in cure.
In subsequent years, additional cases of patients with diffuse
lymphadenopathy and the histologically characteristic CD
lymph node architecture were identified (Keller et al, 1972;
Gaba et al, 1978; Martin et al, 1985). These series also revealed
a new variant of CD, which differed from the original in two
important ways (Flendrig, 1969). First, the germinal centres in
E-mail: [email protected]
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
doi:10.1111/j.1365-2141.2004.05311.x
Review
the involved lymph nodes differed little from normal histology
and showed no evidence of hyalinization. However, concentric
sheets of plasma cells surrounded the germinal centres and
were prominent in the interfollicular space, which also lacked
the characteristic hyper-vascularity (Fig 1). In addition,
patients uniformly presented with a host of systemic symptoms
that were uncommon in the previously described variant. This
novel histological variant of CD was termed the ‘plasma cell’
variant (PCV), to contrast it with the ‘hyaline vascular’ variant
(HVV) that was originally described. The recognition of both
patients with localized lymphadenopathy and disseminated
disease led to an additional clinical categorization of CD:
‘unicentric’ (UCD) versus ‘multicentric’ (MCD).
Most recently, a third ‘subvariant’, known as ‘plasmablastic
MCD’, has been described in association with particularly
aggressive cases of MCD. In the first series to describe such a
variant, CD patients with POEMS syndrome (polyneuropathy,
organomegaly, endocrinopathy, monoclonal proteins and skin
changes), also known as Crow-Fukase, were found to have
lymph nodes which resembled those in PCV, but also had large
plasma cells in the mantle zone with copious cytoplasm and
prominent single or multiple nucleoli (Menke et al, 1996,
2000). A second series found the variant to be associated with
HHV-8 infection and progression to plasmablastic lymphoma
(Dupin et al, 2000).
As the aetiology of CD has not been definitively established,
it remains controversial as to whether CD variants represent
different ends of the same spectrum of disease or whether they
are entirely separate disease entities. The recent association of
HHV-8 infection with both HVV and PCV MCD, as discussed
below, and the finding of both HVV and PCV in the same
lymph node (Flendrig, 1969) argue strongly in favour of a
single disease with several variants, as summarized in Table I.
Pathophysiology
Careful clinical and laboratory investigations of patients with
the different CD variants has enabled a greater understanding
of the pathophysiology of CD. From the first reported case
series, the unique histological pattern seen in lymph nodes was
attributed to a ‘chronic non-specific inflammatory process’
(Castleman et al, 1956). The similarity between the abnormal
nodal histology in both variants of CD and the lymph nodes
associated with chronic viral infections spurred a search for a
viral pathogen(Keller et al, 1972). The increased vascularity
that hallmarks CD suggested to some that an angiogenic factor
may play a role in the genesis of the disease (Frizzera, 1988).
Similarly, the proliferation of plasma cells was hypothesized to
be the result of either exogenous (cytokines) or endogenous
(clonal proliferation) stimulation. Investigations over the past
five decades have enabled the development of an incomplete
model of CD pathogenesis that incorporates each of these
aspects.
Viral stimulation
Fig 1. Typical histopathology of hyaline vascular and plasma cell
variants of castleman disease (original magnification · 40). (A) Photomicrograph of hyaline vascular variant Castleman disease showing a
germinal centre with vascular proliferation (solid arrows), eosinophilic
cells with copious cytoplasm (arrowhead), sheets of plasma cells (P)
and vascularization of the interfollicular space (open arrow). (B)
Photomicrograph of plasma cell variant Castleman disease showing a
germinal centre with sheets of plasma cells (P) both in the germinal
centre and interfollicular space (*), and the absence of vascular proliferation.
4
The information gathered from both clinical and pathological
series of patients with CD led early investigators to search for a
viral pathogen in the aetiology of CD. The symptoms common
to many patients with CD, including indolent fever and
lymphadenopathy, as well as the description of mononuclear
cells with multiple nucleoli that resembled Reed–Sternberg
cells in the lymph node mantle zone (Castleman et al, 1956;
Keller et al, 1972), suggested that Epstein–Barr Virus (EBV)
could play a causative role in the development of CD.
Hanson et al (1988) sought EBV DNA by viral genomic
probes in lymph nodes from eight patients with CD, including
four with localized disease and four with systemic symptoms.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
Table I. Categorization and characteristics of Castleman disease (CD).
Characteristic
Unicentric hyaline vascular variant
Histopathology
Germinal centres involved: usually
‘involuted’ (hyalinized and
lymphocyte depleted)
Interfollicular region: hyperplastic
and fibrotic stroma
Vascularity: increased
Plasma cell infilatration: absent
Male ¼ female
Wide age distribution, median
young adults
Common (80% of unicentric disease)
Single lymph node or chain
Most common in the mediastinum
or cervical lymph nodes
Unknown. May be reactive or
developmental
Demographics
Prevalence
Lymph node
involvement
Aetiology
Unicentric plasma cell variant (PCV)
Multicentric PCV
Germinal centres usually uninvolved,
though mantle zone consists of
concentric sheets of plasma cells
Interfolliuclar region normal with
sheets of plasma cells
Vascular proliferation
?Male > female (c. 2:1)
Male ¼ female
Older age distribution
Wide age distribution, mostly
(fifth–sixth decade)
young adults
Less common (20% of unicentric disease)Least common (10% of all CD)
Single lymph node or chain
Multiple lymph nodes or chains
Most common in the abdomen
Related to increased levels of IL-6
60–100% of cases may be attributable
to infection with HHV-8
Common
Associated symptomsRare
Common
Fevers
Fevers
Nightsweats
Nightsweats
Malaise
Malaise
Associated signs
Marked lymphadenopathy
Localized lymphadenopathy
Marked lymphadenopathy
Splenomegaly
Hepatosplenomegaly
Elevated lactate dehydrogenase
Abnormal
Elevated lactate dehydrogenase
Cytopenias (most commonly anaemia
Cytopenias (most commonly
laboratories
or thrombocytopenia)
anaemia or thrombocytopenia)
Elevated interleukin-6 levels
Elevated C-reactive protein
Elevated interleukin-6 levels
Evidence of infection with
HHV-8 by serology or PCR
Associated diseases
Paraneoplastic pemphigus
Amyloidosis
HIV
Thrombotic thrombocytopenic purpura Renal insufficiency
POEMS Syndrome
Kaposi sarcoma
Amyloidosis
Renal insufficiency
Treatment
Surgical resection
Chemotherapy
Radiation therapy
Antiviral medications
Anti-inflammatories
Monoclonal antibodies to interleukin-6
Long-term sequelae Rare
Progression to lymphoma is common
Only two of the samples had detectable EBV DNA, both in
patients with multicentric disease. These findings were in
contrast to a later series, which detected the EBV non-coding
early RNA (EBER) in the interfollicular region by in situ
hybridization (ISH) in five of 12 (42%) patients with UCD, but
not in a single patient with MCD (Murray et al, 1995). Of
note, none of the EBER-positive lymph nodes had the latent
membrane protein-1 (LMP-1) detected, a staining pattern
more consistent with asymptomatic chronic EBV infection.
Similar results were reported in a study of 20 human
immunodeficiency virus (HIV)-infected persons with MCD,
where zero of five patients with PCV and zero of 15 patients
with a mixed HVV/PCV CD-variant had LMP-1 detected in
lymph nodes with monoclonal antibodies or had EBER by ISH
(Oksenhendler et al, 1996). Finally, the use of the highlysensitive polymerase chain reaction (PCR) paired with Southern blotting of PCR products only identified EBV DNA in two
of four patients with PCV and zero of two patients with HVV
(Corbellino et al, 1996). It is worth noting that EBV DNA may
be found in lymph nodes in conditions other than CD, so its
presence falls short of proof of causation. Briefly, these small
studies argued against EBV as the aetiological agent for CD.
In 1994, a novel gamma-herpesvirus, HHV-8, was detected
in tissue from a patient with HIV-associated KS (Chang et al,
1994). This virus was found to be the HHV, most closely
related to EBV, and subsequently was determined to be
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
5
Review
Table II. Studies examining the proportion of Castleman disease (CD)
cases infected with human herpesvirus 8.
Study
Soulier et al
(1995a)
HIV
status
CD variant
Negative M-hyaline vascular
variant (HVV)
M-plasma cell
variant (PCV)
M-mixed
TOTAL
Positive M-HVV
M-PCV
M-mixed
Total
Kikuta et al (1997) Negative M-PCV
U-HVV
Suda et al (2001)
Negative M-unspecified
Positive
Yamasaki et al
Negative M-PCV
(2003)
Proportion
HHV-8 infected
2/3 (66%)
3/9 (33%)
2/5 (40%)
7/17 (41%)
1/1 (100%)
6/6 (100%)
7/7 (100%)
14/14 (100%)
2/2 (100%)
1/1 (100%)
0/79 (0%)
3/3 (100%)
13/16 (81%)
necessary but not sufficient for the development of KS. KS had
also frequently been reported among patients with MCD.
These findings led researchers to investigate the link between
HHV-8 infection and CD, as summarized in Table II.
Soulier et al (1995a) used PCR and Southern blot analysis to
examine the frequency with which HHV-8 was detected by
PCR in formalin-fixed and fresh-frozen lymph nodes excised
from persons with MCD. Thirty-one patients with all pathological variants, including 17 HIV-negative and 14 HIVinfected persons, were included in this series. Thirty-four HIVuninfected individuals with reactive lymph nodes without
histopathology, characteristic of MCD, were included as
controls. Of the HIV-uninfected participants, seven of 17
(41%) showed evidence of HHV-8 infection, including two of
three (66%) with HVV, three of nine (33%) with PCV and two
of five (40%) with mixed HVV/PCV. All 14 of the HIVinfected persons had HHV-8 detected in the pathological
lymph nodes, including six patients with PCV, one with HVV
and seven with mixed variant MCD. Only one of 34 (3%) of
persons with reactive lymphadenopathy had HHV-8 detectable
in lymph nodes. A larger series of 82 MCD cases from Japan
also examined excised, paraffin-embedded lymph nodes for the
presence of HHV-8 by monoclonal antibodies, ISH and PCR
(Suda et al, 2001). This series found that only three of 82 (4%)
patients had detectable HHV-8, all of whom were HIVinfected. Three additional Japanese patients with MCD were
found to have HHV-8 DNA detected in peripheral blood
mononuclear cells (PBMC) by conventional PCR (Kikuta et al,
1997), but none of the 16 HIV-negative Japanese patients with
MCD had HHV-8 DNA detected in lymph nodes or peripheral
blood by conventional PCR in a separate series(Yamasaki et al,
2003). The use of nested PCR in these samples, however,
detected HHV-8 DNA in lymph nodes from 13 of 16 (81%).
6
Six of seven patients with HHV-8 in the lymph node by nested
PCR had the virus detectable in peripheral blood. The large
discrepancy between these studies is difficult to reconcile, but
may be attributable to differences in methodology. The study
by Soulier et al (1995a), used PCR on fresh-frozen lymph
nodes and the series reported by Kikuta et al (1997) used fresh
PBMCs, while the others relied on preserved specimens. The
use of paraffin-embedded tissues may markedly reduce the
ability to detect genomic DNA in clinical samples (Ben-Ezra
et al, 1991) leading to false-negative results, while the use of
highly sensitive PCR raises the concern for specimen contamination leading to false-positive results.
Three additional lines of evidence support a role for HHV-8
in the pathogenesis of MCD. First, among HIV-infected
individuals, the quantity of HHV-8 DNA in PBMCs or plasma
has been found to correlate with symptoms during flares of
MCD (Grandadam et al, 1997; Bottieau et al, 2000; Oksenhendler et al, 2000; Corbellino et al, 2001; Boivin et al, 2002;
Berezne et al, 2004; Casper et al, 2004). Next, there appears to
be a high degree of HHV-8 replication in patients with MCD.
All HHVs establish a life-long infection, with the virus
alternating between active replication (lytic phase) and quiescent infection with a minimal gene transcription programme
(latent infection). The majority of cells infected with HHV-8 in
patients with KS contain only latent virus, with a small
population of lytic virus (Grundhoff & Ganem, 2004). The
viral gene expression profile in MCD tissue shows that mostly
lytic genes are active in infected cells (Katano et al, 2000,
2001). Finally, as discussed below, administration of antiviral
medications has been associated with the regression of
symptoms in HIV-infected patients with MCD (Casper et al,
2004).
It is clear that HHV-8 plays a significant role in the
pathogenesis of HIV-associated MCD. Definitively establishing
the causality of HHV-8 in the aetiology of CD will prove
challenging. To date, there is no animal model suitable for
studying infection with HHV-8 and the virus does not actively
replicate in cell culture. Prospective studies documenting
HHV-8 infection, prior to the development of CD, would
support a causative role, but the rarity of CD and its indolent
course would require unfeasibly large and lengthy investigations. The best opportunity to examine the role of HHV-8 in
CD may come from carefully-designed case–control series,
where cases and controls are thoroughly evaluated for the
presence of HHV-8 infection using standardized and comprehensive serological and direct virological assessments from
freshly excised tissue and blood. Whether HHV-8 is the sole
aetiologic agent responsible for all variants of HIV-associated
CD, HIV-unassociated MCD or UCD remains to be determined and should be the subject of future investigation.
Angiogenesis
Since the identification of angiogenesis-promoting cytokines,
their role in lymphoproliferative disorders has been debated
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
(Folkman, 1995). Perhaps the cytokine which has sparked the
greatest degree of interest is the human vascular endothelial
growth factor (VEGF). VEGF has been found to specifically
promote the growth of endothelial cells and is capable of
controlling blood vessel formation. Its role in the generation of
the characteristic vascular proliferation in CD has been a target
of limited research.
Foss et al (1997) compared the lymph nodes from eight
patients with CD (variant not specified) to those in tonsillar
tissue from patients with and without infectious mononucleosis. VEGF was detected by ISH in five of eight (63%) germinal
centres and not in the controls (interfollicular spaces or
tonsillar tissue). Among two patients with CD (one U-PCV
and one MCD), both had elevated levels of serum VEGF which
fell to normal with nodal resection and chemotherapy
respectively (Nishi et al, 1999). The supernatants of the
cultured lymph nodes that had been resected from both
patients had VEGF levels that were 100-times higher than a
control node and nearly all plasma cells from the interfollicular
region of both nodes stained strongly positive for VEGF by
ISH. No mention was made of the HHV-8 infection status of
any participant in these studies.
While the elaboration of VEGF may play a role in the
pathophysiology of CD, it seems unlikely to account for all of
the pathological and clinical manifestations of the disease.
Rather, it may be an important step in the causal pathway and
should be considered in any unifying model of the pathogenesis of CD.
Interleukin-6 (IL-6)
In parallel to the search for an angiogenic factor in CD, a role
for cytokines with lymphoproliferative properties was sought.
One potential cytokine with such properties is IL-6, a potent
stimulant for the production of B cells. IL-6 had been
associated with lymphoid malignancies, such as multiple
myeloma and lymphoma, and a series of investigations have
led to the recognition of its importance in the pathogenesis of
CD.
In the first study to examine the association between IL-6
production and the pathological and clinical findings of
patients with CD, Yoshizaki et al (1989) described the
elaboration of IL-6 from germinal centres of lymph nodes in
patients with both U-PCV and MCD. Furthermore, in this
series, serum IL-6 levels were elevated in the patient with
U-PCV along with hypergammaglobulinaemia, organomegaly
and elevated acute phase reactants. All symptoms and laboratory abnormalities resolved with surgical resection of the
node, which was coincident with declines in serum IL-6 levels.
The findings in this early study were corroborated by studies in
mice, where a murine IL-6 gene expressed in mice via a
retroviral vector caused a syndrome indistinguishable from
MCD in humans (Brandt et al, 1990). Series of patients
observed during symptomatic episodes of MCD have confirmed that serum IL-6 levels are elevated to values seen
infrequently with other disease processes and resolve with
treatment (Beck et al, 1994; Nishimoto et al, 2000; Oksenhendler et al, 2000).
A number of different mechanisms for the stimulus of IL-6
production have been proposed. Dysregulation of IL-6
production or the cell-signalling pathway downstream of the
IL-6 receptor have been hypothesized to play a role in a
number of pathologic conditions and may explain the
endogenous production of this human cytokine. Another
possible source of IL-6 production in CD may be from cells
infected with HHV-8. HHV-8 has been shown to produce a
viral analogue of IL-6 (vIL-6) with approximately 50%
similarity to the human IL-6 (hIL-6) gene on an amino acid
level (Moore et al, 1996b). hIL-6 binds the gp130 cellular
receptor and activates the Janus kinase/signal transducers and
activators of transcription (Jak/Stat) cell signalling pathway
through formation of a heterodimer with IL-6 binding protein,
IL-6Ra (Kishimoto et al, 1995). vIL-6 may also bind IL-6Ra
and complex with gp130 to activate the downstream Jak/Stat
pathway (Aoki et al, 2000). The expression of vIL-6 in mice
resulted in a similar clinical picture to the expression of hIL-6,
with increased haematopoesis in all lineages, plasmacytosis
observed in lymph nodes and organomegaly (Aoki et al, 1999).
vIL-6 has been demonstrated to induce the production of hIL6 in cells harvested from the lymph node of a patient with
MCD, providing a link between the higher levels of hIL-6
observed in CD and infection with HHV-8. The expression of
vIL-6 may also link the proliferation of plasma cells and vessels
seen in CD, as VEGF levels in the supernatant of vIL-6
expressing cells have been shown to be several times higher
than the same cells without the expression of vIL-6(Aoki et al,
1999). A role of HHV-8 and vIL-6 in CD has also been
corroborated in several observational studies. vIL-6 is expressed in the lymph nodes of HIV-negative (Parravinci et al,
1997; Menke et al, 2002) and HIV-positive (Cannon et al,
1999) persons with CD. In the peripheral blood, elevated levels
of vIL-6 in a patient symptomatic with HHV-8-associated
MCD regressed with prednisone and foscarnet therapy (Aoki
et al, 2001).
Together, these studies provide compelling evidence for the
importance of human and viral IL-6 in the pathophysiology of
CD, but again raise further questions regarding their exact
roles in the variants of CD.
Clonality
Castleman disease is often categorized within the family of
lymphoproliferative disorders, among which it is common to
find clonal populations of affected cells and cytogenetic
rearrangements. Limited studies have failed to uniformly
reveal clonal immunoglobin or T-cell receptor gene rearrangements in tissue from CD (Hanson et al, 1988; Hall et al, 1989;
Ohyashiki et al, 1994; Soulier et al, 1995b; Cokelaere et al,
2002) (Table III). A review of four cases of CD did not identify
a single case of immunoglobin gene rearrangement or
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
7
Review
Table III. Summary of studies to determine the clonality of Castleman disease (CD).
Study
Castleman variant
Method(s) for determining clonality
Proportion of cases found to be clonal
Hanson et al
(1988)
Unicentric
Immunoglobin and T-cell
receptor gene rearrangements
0/4 (0%)
Hall et al (1989)
Multicentric
M-plasma cell
variant (PCV)
(1)Lamba/IgA assessment
(2) Immunoglobin and T-cell
receptor gene rearrangements
Ohyashiki et al
(1994)
M-PCV
(1)Lamba/IgA assessment
(2) Immunoglobin and T-cell
receptor gene rearrangements
Menke and DeWald
(2001)
1 U-hyaline vascular
variant (HVV)
3 M-PCV
U-HVV
Immunoglobin and T-cell
receptor gene rearrangements
Cokelaere et al
(2002)
(1) Cytogenetic testing
(2) Immunoglobin and T-cell
receptor gene rearrangements
cytogenetic abnormality, leading to the conclusion that these
factors are unlikely to be a major contributor in the
development of CD (Menke & DeWald, 2001).
A unifying model of CD pathogenesis
Important pieces of the chain of events leading to the genesis
of CD remain unclear, but a proposed unified model is as
follows. The initial step in the development of CD appears to
be the production of IL-6 by B cells in the lymph node
mantle zone, stimulated in the majority of cases by HHV-8
infection and in a minority of cases by a heretofore
unidentified exogenous or endogenous factor. Local elaboration of IL-6, and in turn VEGF, produces the characteristic
B-cell proliferation and vascularization of CD. In patients
with multicentric disease, systemic symptoms may result from
the circulation of IL-6 or IL-6-producing B cells, the
generation of excess antibodies or disseminated HHV-8
infection.
3/4 (75%)
(1) 2/5 (40%) with lamba/IgA
restriction
(2) 3/5 (60%) with immunoglobin
gene rearrangements
2/2 (100%) with lambda chain
clonal rearrangement, but only
1/2 (50%) with expression of
light chain restriction. 0/2 (0%)
with Ig heavy chain or T-cell
receptor changes
0/4 (0%) had immunoglobin and
T-cell receptor gene rearrangements
Clonal aberration detected on long
arm of chromosome 12 without
immunoglobin and T-cell receptor
gene rearrangements
in approximately 70% of patients with CD (Fig 2). There is no
predilection for either gender and while patients present with a
range of ages, the median age tends to be in the fourth decade.
By definition, a single node or chain of lymph nodes is
involved in U-HVV. The involved node is typically large, with
a median diameter of 6–7 cm (range of 1–25 cm). Initial case
series found the mediastinum to be the most common location
for lymph node enlargement, but subsequent series have found
M-PCV
10%
U-PCV
18%
Clinical presentation
The clinical manifestations of the CD variants have been welldescribed in several large case series (Keller et al, 1972;
Frizzera, 1988; Peterson & Frizzera, 1993; Herrada et al,
1998) and are discussed individually below.
U-HVV
72%
Unicentric hyaline vascular variant (U-HVV)
Both the first variant of CD to be identified and the most
common variant encountered clinically today, U-HVV occurs
8
Fig 2. Distribution of Castleman variants in the population.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
cervical, abdominal and axillary lymphadenopathy to be
equally as common (Castleman et al, 1956; Keller et al, 1972;
Herrada et al, 1998). The presenting symptoms of patients
with U-HVV CD vary according to the site of involvement.
Many patients with mediastinal or abdominal lymphadenopathy either are asymptomatic and alerted to their condition
via radiographic studies or surgical procedures for other
conditions, or come to medical attention because of compressive symptoms. Patients, themselves, often recognize cervical,
inguinal or axillary involvement which is then brought to the
attention of their health care provider. U-HVV lesions most
often present as solitary masses with intense homogeneous
contrast enhancement on computed tomography (CT)
(Ko et al, 2004) and positron emission tomography may not
be useful for distinguishing CD from malignancy (Reddy &
Graham, 2003). In contrast to the plasma cell and multicentric
variants of CD, U-HVV is rarely (<10%) associated with
systemic symptoms. Diagnosis of CD should be established by
excisional lymph node biopsy, with the architecture of the
entire germinal centre and interfollicular zone preserved for
analysis by experienced histopathologists. The normal appearance of cells isolated from the entire lymph node may lead to a
failure to diagnose CD with the use of fine needle aspiration
(Cangiarella et al, 1997).
Unicentric plasma cell variant (U-PCV)
Unicentric plasma cell variant probably accounts for <20% of
all CD variants. It is characterized by the hypertrophy of a
single lymph node chain, although involvement of a solitary
lymph node is unusual (Keller et al, 1972). Abnormal nodes
are most frequently found in the abdomen (Frizzera, 1988).
Like U-HVV, the disease occurs equally in men and women,
and has been reported among younger patients (third decade).
Unlike U-HVV, the majority of U-PCV patients present with
constitutional symptoms. Anaemia and elevated sedimentation
rates are present in most cases, observed in 90% and 80%
respectively. These laboratory anomalies in the setting of
lymphadenopathy may raise the suspicion of U-PCV CD, but
ultimately an excisional lymph node biopsy showing the
characteristic sheets of plasma cells in the interfollicular space
is required for diagnosis.
Multicentric plasma cell variant (M-PCV)
Multicentric plasma cell variant CD is the least commonly
encountered CD variant, but presents with the most protean
manifestations. Affected patients are typically older than
those with unicentric disease (median age fifth–sixth decade).
A predilection for male sex had initially been reported in the
literature (Frizzera et al, 1985; Weisenburger et al, 1985), but
the total cases in these series number less than three dozen
and subsequent studies have not found that the prevalence of
the disease varies by gender (Herrada et al, 1998; Bowne et al,
1999; Chronowski et al, 2001). Patients frequently come to
medical attention for the evaluation of systemic symptoms.
Fever is reported by most patients, while approximately half
will experience weight loss and night sweats (Peterson &
Frizzera, 1993; Chronowski et al, 2001). Organomegaly is
inconsistent, with splenomegaly reported in 33–79% of
patients; hepatomegaly, almost exclusively in the presence
of splenomegaly, may occur in up to 63% of M-PCV
patients. Thirteen per cent of patients in three case series
were found to have KS concurrent with CD, as reviewed in
Peterson and Frizzera (1993). A number of abnormal
laboratory results are seen, including uniformly elevated
sedimentation rates, frequent anaemia (up to 90%), thrombocytopenia or transaminitis (nearly two-third of the patients)
(Peterson & Frizzera, 1993). There are no characteristic
features of M-PCV on CT and uptake of gallium on
scintigraphy is inconsistent (Stansby et al, 1991; Okamoto
et al, 2003).
One of the most devastating diseases associated with M-PCV
is the POEMS syndrome, seen in up to 15% of MCD cases
(Peterson & Frizzera, 1993). POEMS syndrome is thought to
result from a plasma-cell dyscrasia and the subsequent
production of monoclonal proteins. Lymph node biopsies
are not routinely performed as part of the management of
POEMS syndrome, but the few large case series have
documented MCD in 11–24% of POEMS cases (Nakanishi
et al, 1984; Soubrier et al, 1994; Dispenzieri et al, 2003).
Patients dually-diagnosed with MCD and POEMS may be
more likely to be infected with HHV-8. In a small series of
patients with MCD and POEMS, six of seven (85%) had HHV8 detected in lymph nodes by PCR, and all had serum
antibodies to HHV-8 (Belec et al, 1999a). The prevalence of
HHV-8 in POEMS patients with MCD is nearly five times that
of POEMS patients without MCD (75% vs. 13% in a study of
22 patients) (Belec et al, 1999b). Therefore, it is reasonable to
test patients presenting with MCD who have evidence of
neuropathy for infection with HHV-8.
Clinical course and prognosis
Few studies exist because of the natural history of untreated
CD. The diversity of patients and therapies in the various CD
series makes drawing conclusions about natural history and
prognosis challenging.
Unicentric CD is almost universally cured after the resection
of involved lymph node(s) and has not been associated with
increased mortality. Rare patients with U-PCV may require
additional therapy after resection for persistent systemic
symptoms, but the course of these patients has not been
well-characterized.
After the initial presentation of patients with MCD, 33–50%
experience symptoms that recur repeatedly over the course of
several weeks to over 4 years (Frizzera et al, 1985; Weisenburger et al, 1985). In the four largest series of MCD, median
survival ranged from 14 to 30 months, although some patients
lived only several weeks following diagnosis, while others were
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
9
Review
reported to be alive at 20 years (Frizzera et al, 1985; Weisenburger et al, 1985; Oksenhendler et al, 1996; Herrada et al,
1998). Death in MCD is either caused by sepsis, systemic
inflammation leading to multi-organ system failure, or the
development of malignancy (most commonly lymphoma).
Careful attention to infectious and neoplastic complications, as
well as treatment of associated conditions such as HIV may
lead to meaningful increases in the life expectancy of patients
with MCD.
(Oksenhendler et al, 2002). Of them, three developed primary
effusion lymphoma, five developed extranodal NHL and an
additional six were diagnosed with an aggressive plasmablastic
lymphoma. It was estimated from this series that the 2-year
probability of developing NHL after MCD diagnosis was 24%
and neither HIV plasma RNA level nor CD4 count was
predictive. A similar study of 11 patients followed for
48 months in Australia found that four (37%) developed
NHL (Loi et al, 2004).
Special populations
Treatment
Paediatrics. The clinical manifestations of CD in children that
have been reported in the literature differ little from those
observed among adults (Salisbury, 1990; Parez et al, 1999).
Presentation at <12 years of age is unusual and it has been
suggested that the course of MCD among children is less
morbid. The proportion of childhood CD cases which may be
attributable to infection with HHV-8 has not been
determined.
Early interventions in the treatment of CD were iterations of
standard therapy for lymphoproliferative diseases, including
surgical excision, cytoreductive chemotherapy and radiation
therapy. With a greater understanding of CD pathogenesis,
therapies directed at specific targets have been developed and
show great promise.
HIV. Lymphadenopathy is frequently encountered among
patients infected with HIV and often requires excisional
biopsy for aetiological diagnosis. The proportion of HIVinfected patients with lymphadenopathy attributable to CD has
not been studied, but a number of published series suggest that
the condition is not rare. It also remains to be determined
whether the frequent observation of CD in patients with HIV is
attributable to the higher prevalence of HHV-8 co-infection
among HIV-infected patients or whether HIV-infection itself
predisposes to the development of CD.
HIV-associated CD is almost always either M-PCV or
multicentric mixed variant (Oksenhendler et al, 1996). Fever
and splenomegaly are universal and commonly remit spontaneously after several weeks. Anaemia is present in approximately half of the HIV-infected patients with MCD, but all will
have elevated C-reactive protein (CRP) and HHV-8 detected
in PBMCs during symptomatic flares (Grandadam et al, 1997;
Oksenhendler et al, 2000; Aaron et al, 2002). Symptomatic
flares of MCD may occur at any CD4 count, with reports in the
literature from 0Æ001 to >1Æ0 · 109 T cells/l (Grandadam et al,
1997; Oksenhendler et al, 2000; Aaron et al, 2002; Casper et al,
2004; Loi et al, 2004). There seems to be no clear effect of
antiretroviral therapy on the course of MCD, although data are
limited. Three patients treated with highly-active antiretroviral
therapy were noted to have a ‘rapidly progressive’ course of
MCD shortly after initiating treatment (Zietz et al, 1999).
Improvements in T-cell count and suppression of HIV
replication did not affect the course of MCD in five of seven
patients in one series (Aaron et al, 2002) and two of three in
another (Casper et al, 2004).
Patients with MCD and HIV-infection are at an increased
risk of developing non-Hodgkin’s lymphoma (NHL). Sixty
HIV-infected patients with MCD were followed for a median
of 20 months and a total of 14 of 60 (23%) developed NHL
Case series have repeatedly illustrated that surgery is almost
always curative for unicentric disease of either the hyaline
vascular or PCV (Castleman et al, 1956; Keller et al, 1972;
Herrada et al, 1998; Bowne et al, 1999). Because of the
disseminated nature of the lymphadenopathy with multicentric disease, complete surgical debulking is rarely possible. The
few patients with MCD in whom surgery has been reported
have not had meaningful or lasting improvements in their
disease symptoms (Herrada et al, 1998; Bowne et al, 1999). As
splenomegaly is a constant feature of MCD, diagnostic or
therapeutic splenectomy is often performed but has not been
shown to be of clinical benefit.
10
Surgical excision
Cytoreductive therapy
Chemotherapy for MCD has been modelled on regimens
designed for the treatment of NHL. Accordingly, the most
common regimen reported in the literature is the use of
cyclophosphamide, vincristine, doxorubicin and either prednisone (CHOP) or dexamethasone (CVAD), both with mixed
success. Two series documented the induction of remission
with chemotherapy lasting from 1 to 10 years in four of six
(67%) treated with CVAD and two of four (50%) patients
treated with CHOP (Herrada et al, 1998; Chronowski et al,
2001). Other series have documented minimal success with
cyclophosphamide, vincristine and prednisone, and
cyclophosphamide, vincristine, procarbazine and prednisone
(Frizzera et al, 1985; Weisenburger et al, 1985). A host of other
regimens have been described in case reports, but in the
absence of larger case series or controlled trials, efficacy is
difficult to assess. The HHV-8 infection status was not
reported for any patient in these case series and whether
HHV-8 infection influences the response to chemotherapy is
not known.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
Radiation therapy
A recent review of 18 cases of CD that were treated with
radiotherapy found that 13 patients (72%) had a complete or
partial response to radiotherapy (Chronowski et al, 2001).
Only three of the 13 responders (23%) had multicentric
disease; the benefit in these patients may have been attributable
to adjuvant chemotherapy or corticosteroids that was concurrently administered.
Immune modulators
Steroids. The use of corticosteriods to control the intense
inflammation associated with multicentric disease is common,
but has not been subjected to clinical trials. Six of 15 (40%)
patients in one series were treated with glucocorticosteroids, of
whom two had ‘control of disease’ during long-term
administration and four saw no lasting response (Frizzera
et al, 1985), while a ‘partial response’ was documented in three
of five (60%) MCD patients treated exclusively with
prednisone (Weisenburger et al, 1985). The few patients
receiving prednisone alone in other case series saw transient
improvements while on the drug (Herrada et al, 1998; Bowne
et al, 1999). Prolonged therapy with low-dose prednisone
(10 mg/d) was successful in two patients with M-HVV
(Summerfield et al, 1983), but failed in a patient with
aggressive M-PCV (Bertero et al, 2000). Long-term
corticosteroids may be associated with a high risk of
bacterial infection in MCD patients, as a large number were
noted to die of sepsis during therapy (Frizzera et al, 1985;
Bowne et al, 1999).
Interferon-a. Interferon-a has both immunoregulatory and
antiviral properties, making it a plausibly effective therapy for
patients with MCD. Two patients with HIV-associated MCD
have been reported to have lasting remissions after
administration of interferon-a chronic therapy, one HHV-8
infected patient with a dose of 5 million units thrice weekly
(Kumari et al, 2000) and the other with 5 million units weekly
whose HHV-8 infection status was not stated (Nord & Karter,
2003). One HIV-negative patient with MCD (HHV-8 status
unknown) was observed to relapse 4 years after receiving
1 year of 3–5 million units of interferon-a thrice weekly
(Andres & Maloisel, 2000). All patients in these reports
tolerated the drug well. The relative importance of the antiviral
and immunomodulatory properties of interferon has not been
characterized and therefore it remains to be seen whether it is
an effective therapy for MCD in patients who are not infected
with HHV-8.
All-trans retinoic acid. All-trans retinoic acid (ATRA) has
been shown to have antiproliferative effects (Kane et al, 1996)
and may also decrease IL-6-dependent cell signalling (Zancai
et al, 2004). It was hypothesized that both these properties
could be beneficial in the treatment of MCD, and a case
report describing its successful administration in a HIV and
HHV-8 uninfected woman has been described (Rieu et al,
1999).
Thalidomide. Similar to interferon-a and ATRA, thalidomide
also has immunomodulatory properties (Franks et al, 2004).
Thalidomide, however, may act specifically to decrease the
production of IL-6, but also possess anti-angiogenic
properties. Two patients have been reported to receive
thalidomide. One HIV- and HHV-8 infected man had
improvements in platelet count but persistent constitutional
symptoms with thalidomide and etoposide (Jung et al, 2004),
and one HIV-negative woman (HHV-8 infection status not
stated) had a complete response lasting over 1 year with
300 mg of thalidomide daily (Lee & Merchant, 2003).
Monoclonal antibodies
Anti-IL-6 monoclonal antibody. A 27-year-old man with MPCV CD was the first patient to receive anti-IL-6 antibodies for
the treatment of CD (Beck et al, 1994). Administration of a
murine monoclonal antibody (BE-8) led to a rapid
improvement in symptoms and CRP, haematocrit, platelet
count and albumin, while levels of serum IL-6 rose to over
10,000 pg/ml. After 84 d of continuous administration, the
drug was discontinued; symptoms and laboratory
abnormalities quickly returned. It was hypothesized that the
generation of mice anti-IL antibodies failed to completely
neutralize hIL-6 in serum, resulting in an increase in the serum
IL-6 level via homeostatic mechanisms. Therefore, a new
product (atlizumab, Roche Pharmaceuticals, Basel,
Switzerland) with two substantial changes was developed: the
target of this new drug was the IL-6 receptor and it was
engineered to be a hybrid between mouse and human
antibodies to avoid the development of auto-antibodies with
repeated administration (Sato et al, 1993). Treatment of seven
HIV and HHV-8 negative patients with once- or twice-weekly
intravenous infusions resulted in resolution of symptoms and
normalization of laboratory values over 2 months, but
discontinuation of the infusions led to relapse within
2 weeks (Nishimoto et al, 2000). Re-exposure did not result
in the generation of antibodies to the drug. The long-term
effects of IL-6 receptor blockade are not known, but none was
reported in this series.
Rituximab. Plasma cells in the mantle zone of some patients
with HHV-8 positive and HHV-8 negative M-PCV CD have
been shown to express the cell surface marker CD20 (Hall et al,
1989; Dupin et al, 2000; Gholam et al, 2003). The drug
rituximab is a monoclonal antibody to CD20 that targets cells
expressing this surface marker for death by either complement
or cytotoxic cells. Successful therapy with rituximab has been
reported in a small number of patients with and without HIV
and HHV-8 infection. Eight patients with HIV and HHV-8associated MCD received infusions of rituximab (Corbellino
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
11
Review
et al, 2001; Marcelin et al, 2003; Kofteridis et al, 2004;
Newsom-Davis et al, 2004). In the largest series, three of five
(60%) achieved a complete response, which was durable for as
long as 14 months and the other two died of multi-organ
system failure (Marcelin et al, 2003). It is notable that the two
patients who did not respond, both presented with ‘severe
haematologic autoimmune phenomenon’, and that two of the
four patients with KS saw a worsening of their KS while
receiving rituximab. Three HIV-negative MCD patients,
including two without evidence of HHV-8 infection, also
have been reported in the literature to respond to rituximab.
All three patients, however, received either previous or
concurrent therapy, including steroids (Ide et al, 2003),
chemotherapy (Gholam et al, 2003) and cidofovir (Marietta
et al, 2003).
receiving any one therapy, the use of multiple therapies
together, the relapsing and remitting nature of CD and
continuing uncertainties regarding the pathophysiology of the
disease. It seems clear that patients with unicentric disease are
almost always cured by surgery alone and that radiotherapy
may be a viable option for patients who are poor surgical
candidates. A myriad of treatment options exist for patients
with MCD and one approach to treatment may be to consider
other factors associated with MCD. Ganciclovir, interferon-a
or rituximab may be the best treatment options in patients
with HHV-8 infection, while CHOP or CVAD may be most
appropriate for patients with severe systemic manifestations of
MCD. Randomized trials are desperately needed to determine
those treatment regimens that are most effective.
Approach to the patient with suspected CD
Antiviral therapy
Several antiviral medications have shown the ability to
effectively inhibit the replication of HHV-8 in vitro, including
ganciclovir, foscarnet and cidofovir (Kedes & Ganem, 1997;
Medveczky et al, 1997; Neyts & De Clercq, 1997). A handful of
HHV-8-associated MCD patients have been treated with
antiviral medications, with mixed success. Of four patients
treated with foscarnet, two had no improvement (Bottieau
et al, 2000; Senanayake et al, 2003) and two had persistent
remission for 12–24 months (Revuelta & Nord, 1998; Nord &
Karter, 2003). Seven patients treated with a combination of
cidofovir and chemotherapy exhibited no response in either
symptomatology or HHV-8 viraemia (Corbellino et al, 2001;
Senanayake et al, 2003; Berezne et al, 2004). The use of
ganciclovir or the oral derivative valganciclovir, however,
reduced HHV-8 viraemia in three patients and led to
remissions lasting 12–18 months (Casper et al, 2004). A
number of factors may explain the heterogeneity in the
response to antiviral therapy for HHV-8-associated MCD.
First, as the current in vitro models may not adequately
characterize the in vivo efficacy of these drugs, clinical studies
to determine which of the antiviral medications has the
greatest effect on HHV-8 are needed. Next, if the symptoms of
HHV-8-associated MCD are attributable, at least in part to the
production of vIL-6, then the current medications that inhibit
DNA synthesis may fail to uniformly abort the production of
this early-lytic gene product (Zoeteweij et al, 1999). Finally,
the optimal time to administer antivirals is not currently
understood. If the relationship between MCD and HHV-8 is
akin to that of post-transplant lymphoproliferative disorder
and EBV, then the use of antivirals prior to cell transformation
may be a successful strategy.
Conclusions
Drawing definitive conclusions regarding the optimal treatment of CD from the current medical literature is limited by
the small number and heterogeneous characteristics of patients
12
A diagnosis of CD most often is not entertained until its
characteristic features are noted on an excisional lymph node
biopsy. Prior to biopsy, however, clinical suspicion for CD
should be elevated in patients who have diseases often
associated with CD, including KS and POEMS syndrome. A
suggested algorithm for the evaluation and management of
patients suspected to have CD is shown in Fig 3. Patients
with lymph node histology consistent with CD should first
have other causes of similar-appearing reactive lymphadenopathy ruled out. These include rheumatoid arthritis, lupus,
Sjörgen syndrome, HIV infection, lymphoma and drug
sensitivity. To differentiate between localized and systemic
disease, obtaining a complete blood count (CBC), CRP, and
liver function tests (LFTs) are helpful along with a radiologic
assessment of cervical, thoracic, abdominal and pelvic
lymphadenopathy. Testing for serum interleukin-6 and
plasma or PBMC HHV-8 levels are not uniformly available
at all laboratories, but should be strongly encouraged in
patients with systemic symptoms to help select the most
appropriate therapy. Appropriate follow up should be
tailored to CD variant and symptoms. Patients with unicentric disease without systemic involvement should have an
additional radiological assessment 6–12 months after therapy
to verify cure, with additional testing or therapy only pursued
with new symptoms. Patients with MCD need to be followed
more closely, with repeat CBC, LFT, CRP and radiology at
regular intervals or when symptoms suggest recurrence. A
suggested algorithm is depicted in Fig 3.
In summary, five decades of steady research into the
aetiology and management of the unusual and fascinating
lymphoproliferative disorder named after Dr Benjamin Castleman has resulted in many answers, but generates a myriad
of questions. Meticulous review of the histopathology in
affected lymph nodes in conjunction with astute clinical
observations has enabled the categorization of CD into
variants with meaningful treatment and prognostic implications. Basic science work has elucidated many of the
important components of CD pathophysiology, including
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
Fig 3. Suggested approach to the patient
with Castleman disease. LN, lymph node;
LAN, lymphadenopathy; LFT, liver function
test; ANA, anti-nuclear antibodies; Bx,
biopsy; Dx, diagnosis; RF, rheumatoid
factor; EIA, enzyme immunoassay; WB,
Western blot; RPR, rapid plasma reagin.
the role of IL-6 production, HIV and HHV-8 infection and
angiogenesis. Innovative treatment strategies have been
developed that appear to meaningfully affect the natural
history of CD. In the coming years, however, fundamental
questions remain to be answered. Why is CD seen only in a
small proportion of patients infected with HHV-8? Are all
variants of CD caused by HHV-8 infection? What is the
stimulus for the production of IL-6 and angiogenesis in the
absence of HHV-8 infection? Why do some patients present
with localized disease and other systemic? How are
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
13
Review
recurrences of CD initiated, and can they be clinically
predicted? Which therapeutic regimens are best, are there
subsets of patients who benefit more from one over another,
and do any prevent the development of lymphoma or death
in the most serious cases? The next half-century promises to
bring great advances in understanding the aetiology of CD, in
turn translating to novel therapeutic approaches for patients
afflicted with this disease.
Acknowledgements
I am indebted to Dr Anna Wald for her thoughtful comments
and review of the manuscript, as well as her infectious
enthusiasm for advancing our understanding and treatment of
Castleman Disease.
Grant support: National Institute of Health, K23 1AI054162.
References
Aaron, L., Lidove, O., Yousry, C., Roudiere, L., Dupont, B. & Viard,
J.P. (2002) Human herpesvirus 8-positive Castleman disease in
human immunodeficiency virus-infected patients: the impact of
highly active antiretroviral therapy. Clinical Infectious Diseases, 35,
880–882.
Andres, E. & Maloisel, F. (2000) Interferon-alpha as first-line therapy
for treatment of multicentric Castleman’s disease. Annals of Oncology, 11, 1613–1614.
Aoki, Y., Jaffe, E.S., Chang, Y., Jones, K., Teruya-Feldstein, J., Moore,
P.S. & Tosato, G. (1999) Angiogenesis and hematopoiesis induced
by Kaposi’s sarcoma-associated herpesvirus-encoded interleukin-6.
Blood, 93, 4034–4043.
Aoki, Y., Jones, K.D. & Tosato, G. (2000) Kaposi’s sarcoma-associated
herpesvirus-encoded interleukin-6. Journal of Hematotherapy and
Stem Cell Research, 9, 137–145.
Aoki, Y., Tosato, G., Fonville, T.W. & Pittaluga, S. (2001) Serum viral
interleukin-6 in AIDS-related multicentric Castleman disease. Blood,
97, 2526–2527.
Beck, J.T., Hsu, S.M., Wijdenes, J., Bataille, R., Klein, B., Vesole, D.,
Hayden, K., Jagannath, S. & Barlogie, B. (1994) Brief report: alleviation of systemic manifestations of Castleman’s disease by
monoclonal anti-interleukin-6 antibody. The New England Journal of
Medicine, 330, 602–605.
Belec, L., Mohamed, A.S., Authier, F.J., Hallouin, M.C., Soe, A.M.,
Cotigny, S., Gaulard, P. & Gherardi, R.K. (1999a) Human herpesvirus 8 infection in patients with POEMS syndrome-associated
multicentric Castleman’s disease. Blood, 93, 3643–3653.
Belec, L., Authier, F.J., Mohamed, A.S., Soubrier, M. & Gherardi, R.K.
(1999b) Antibodies to human herpesvirus 8 in POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, skin changes) syndrome with multicentric Castleman’s disease. Clinical
Infectious Diseases, 28, 678–679.
Ben-Ezra, J., Johnson, D.A., Rossi, J., Cook, N. & Wu, A. (1991) Effect
of fixation on the amplification of nucleic acids from paraffin-embedded material by the polymerase chain reaction. Journal of Histochemistry and Cytochemistry, 39, 351–354.
Berezne, A., Agbalika, F. & Oksenhendler, E. (2004) Failure of cidofovir in HIV-associated multicentric Castleman disease. Blood, 103,
4368–4369; author reply 4369.
14
Bertero, M.T., De Maestri, M. & Caligaris-Cappio, F. (2000) Cyclophosphamide/cyclosporin-A treatment of multicentric Castleman’s
disease with Kaposi’s sarcoma. Haematologica, 85, 216–217.
Boivin, G., Cote, S., Cloutier, N., Abed, Y., Maguigad, M. & Routy, J.P.
(2002) Quantification of human herpesvirus 8 by real-time PCR in
blood fractions of AIDS patients with Kaposi’s sarcoma and
multicentric Castleman’s disease. Journal of Medical Virology, 68,
399–403.
Bottieau, E., Colebunders, R., Schroyens, W., Van Droogenbroeck, J.,
De Droogh, E., Depraetere, K., De Raeve, H. & Van Marck, E. (2000)
Multicentric Castleman’s disease in 2 patients with HIV infection,
unresponsive to antiviral therapy. Acta Clinica Belgica, 55, 97–101.
Bowne, W.B., Lewis, J.J., Filippa, D.A., Niesvizky, R., Brooks, A.D.,
Burt, M.E. & Brennan, M.F. (1999) The management of unicentric
and multicentric Castleman’s disease: a report of 16 cases and a
review of the literature. Cancer, 85, 706–717.
Brandt, S.J., Bodine, D.M., Dunbar, C.E. & Nienhuis, A.W. (1990)
Dysregulated interleukin 6 expression produces a syndrome resembling Castleman’s disease in mice. Journal of Clinical Investigation, 86, 592–599.
Cangiarella, J., Gallo, L. & Winkler, B. (1997) Potential pitfalls in the
diagnosis of Castleman’s disease of the mediastinum on fine needle
aspiration biopsy. Acta Cytologica, 41, 951–952.
Cannon, J.S., Nicholas, J., Orenstein, J.M., Mann, R.B., Murray, P.G.,
Browning, P.J., DiGiuseppe, J.A., Cesarman, E., Hayward, G.S. &
Ambinder, R.F. (1999) Heterogeneity of viral IL-6 expression in
HHV-8-associated diseases. Journal of Infectious Diseases, 180, 824–
828.
Casper, C., Nichols, W.G., Huang, M.L., Corey, L. & Wald, A. (2004)
Remission of HHV-8 and HIV-associated multicentric Castleman
disease with ganciclovir treatment. Blood, 103, 1632–1634.
Castleman, B. & Thowne, V.W. (eds) (1954) Case records of the Massachusetts General Hospital Weekly Clinicopathological Exercises:
Case 40011. The New England Journal of Medicine, 250, 26–30.
Castleman, B., Iverson, L. & Menendez, V.P. (1956) Localized mediastinal lymphnode hyperplasia resembling thymoma. Cancer, 9,
822–830.
Chang, Y., Cesarman, E., Pessin, M.S., Lee, F., Culpepper, J., Knowles,
D.M. & Moore, P.S. (1994) Identification of herpesvirus-like DNA
sequences in AIDS-associated Kaposi’s sarcoma. Science, 266, 1865–
1869.
Chronowski, G.M., Ha, C.S., Wilder, R.B., Cabanillas, F., Manning, J.
& Cox, J.D. (2001) Treatment of unicentric and multicentric Castleman disease and the role of radiotherapy. Cancer, 92, 670–676.
Cokelaere, K., Debiec-Rychter, M., De Wolf-Peeters, C., Hagemeijer, A.
& Sciot, R. (2002) Hyaline vascular Castleman’s disease with
HMGIC rearrangement in follicular dendritic cells: molecular evidence of mesenchymal tumorigenesis. American Journal of Surgical
Pathology, 26, 662–669.
Corbellino, M., Poirel, L., Aubin, J.T., Paulli, M., Magrini, U., Bestetti,
G., Galli, M. & Parravicini, C. (1996) The role of human herpesvirus
8 and Epstein–Barr virus in the pathogenesis of giant lymph node
hyperplasia (Castleman’s disease). Clinical Infectious Diseases, 22,
1120–1121.
Corbellino, M., Bestetti, G., Scalamogna, C., Calattini, S., Galazzi, M.,
Meroni, L., Manganaro, D., Fasan, M., Moroni, M., Galli, M. &
Parravicini, C. (2001) Long-term remission of Kaposi sarcomaassociated herpesvirus-related multicentric Castleman disease with
anti-CD20 monoclonal antibody therapy. Blood, 98, 3473–3475.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
Dispenzieri, A., Kyle, R.A., Lacy, M.Q., Rajkumar, S.V., Therneau,
T.M., Larson, D.R., Greipp, P.R., Witzig, T.E., Basu, R., Suarez, G.A.,
Fonseca, R., Lust, J.A. & Gertz, M.A. (2003) POEMS syndrome:
definitions and long-term outcome. Blood, 101, 2496–2506.
Dupin, N., Diss, T.L., Kellam, P., Tulliez, M., Du, M.Q., Sicard, D., Weiss,
R.A., Isaacson, P.G. & Boshoff, C. (2000) HHV-8 is associated with a
plasmablastic variant of Castleman disease that is linked to HHV-8positive plasmablastic lymphoma. Blood, 95, 1406–1412.
Flendrig, J.A. (1969) Benign giant lymphoma: the clinical signs and
symptoms and the morphological aspects. Folia Medica, 12, 119–120.
Folkman, J. (1995) Angiogenesis in cancer, vascular, rheumatoid and
other disease. Nature Medicine, 1, 27–31.
Foss, H.D., Araujo, I., Demel, G., Klotzbach, H., Hummel, M. & Stein,
H. (1997) Expression of vascular endothelial growth factor in lymphomas and Castleman’s disease. Journal of Pathology, 183, 44–50.
Franks, M.E., Macpherson, G.R. & Figg, W.D. (2004) Thalidomide.
The Lancet, 363, 1802–1811.
Frizzera, G. (1988) Castleman’s disease and related disorders. Seminars
in Diagnostic Pathology, 5, 346–364.
Frizzera, G., Peterson, B.A., Bayrd, E.D. & Goldman, A. (1985) A
systemic lymphoproliferative disorder with morphologic features of
Castleman’s disease: clinical findings and clinicopathologic correlations in 15 patients. Journal of Clinical Oncology, 3, 1202–1216.
Gaba, A.R., Stein, R.S., Sweet, D.L. & Variakojis, D. (1978) Multicentric giant lymph node hyperplasia. American Journal of Clinical
Pathology, 69, 86–90.
Gholam, D., Vantelon, J.M., Al-Jijakli, A. & Bourhis, J.H. (2003) A case
of multicentric Castleman’s disease associated with advanced systemic amyloidosis treated with chemotherapy and anti-CD20
monoclonal antibody. Annals of Hematology, 82, 766–768.
Grandadam, M., Dupin, N., Calvez, V., Gorin, I., Blum, L., Kernbaum,
S., Sicard, D., Buisson, Y., Agut, H., Escande, J.P. & Huraux, J.M.
(1997) Exacerbations of clinical symptoms in human
immunodeficiency virus type 1-infected patients with multicentric
Castleman’s disease are associated with a high increase in Kaposi’s
sarcoma herpesvirus DNA load in peripheral blood mononuclear
cells. Journal of Infectious Diseases, 175, 1198–1201.
Grundhoff, A. & Ganem, D. (2004) Inefficient establishment of KSHV
latency suggests an additional role for continued lytic replication in
Kaposi sarcoma pathogenesis. Journal of Clinical Investigation, 113,
124–136.
Hall, P.A., Donaghy, M., Cotter, F.E., Stansfeld, A.G. & Levison, D.A.
(1989) An immunohistological and genotypic study of the plasma
cell form of Castleman’s disease. Histopathology, 14, 333–346; discussion 429–332.
Hanson, C.A., Frizzera, G., Patton, D.F., Peterson, B.A., McClain, K.L.,
Gajl-Peczalska, K.J. & Kersey, J.H. (1988) Clonal rearrangement for
immunoglobulin and T-cell receptor genes in systemic Castleman’s
disease. Association with Epstein–Barr virus. American Journal of
Pathology, 131, 84–91.
Herrada, J., Cabanillas, F., Rice, L., Manning, J. & Pugh, W. (1998) The
clinical behavior of localized and multicentric Castleman disease.
Annals of Internal Medicine, 128, 657–662.
Ide, M., Ogawa, E., Kasagi, K., Kawachi, Y. & Ogino, T. (2003) Successful treatment of multicentric Castleman’s disease with bilateral
orbital tumour using rituximab. British Journal of Haematology, 121,
818–819.
Jung, C.P., Emmerich, B., Goebel, F.D. & Bogner, J.R. (2004) Successful treatment of a patient with HIV-associated multicentric
Castleman disease (MCD) with thalidomide. American Journal of
Hematology, 75, 176–177.
Kane, K.F., Langman, M.J. & Williams, G.R. (1996) Antiproliferative
responses to two human colon cancer cell lines to vitamin D3 are
differently modified by 9-cis-retinoic acid. Cancer Research, 56, 623–
632.
Katano, H., Sato, Y., Kurata, T., Mori, S. & Sata, T. (2000) Expression
and localization of human herpesvirus 8-encoded proteins in primary effusion lymphoma, Kaposi’s sarcoma, and multicentric Castleman’s disease. Virology, 269, 335–344.
Katano, H., Sato, Y., Itoh, H. & Sata, T. (2001) Expression of human
herpesvirus 8 (HHV-8)-encoded immediate early protein, open
reading frame 50, in HHV-8-associated diseases. Journal of Human
Virology, 4, 96–102.
Kedes, D.H. & Ganem, D. (1997) Sensitivity of Kaposi’s sarcomaassociated herpesvirus replication to antiviral drugs. Implications for
potential therapy. Journal of Clinical Investigation, 99, 2082–2086.
Keller, A.R., Hochholzer, L. & Castleman, B. (1972) Hyaline-vascular
and plasma-cell types of giant lymph node hyperplasia of the
mediastinum and other locations. Cancer, 29, 670–683.
Kikuta, H., Itakura, O., Ariga, T. & Kobayashi, K. (1997) Detection of
human herpesvirus 8 DNA sequences in peripheral blood mononuclear cells of children. Journal of Medical Virology, 53, 81–84.
Kishimoto, T., Akira, S., Narazaki, M. & Taga, T. (1995) Interleukin-6
family of cytokines and gp130. Blood, 86, 1243–1254.
Ko, S.F., Hsieh, M.J., Ng, S.H., Lin, J.W., Wan, Y.L., Lee, T.Y., Chen,
W.J. & Chen, M.C. (2004) Imaging spectrum of Castleman’s disease.
AJR. American Journal of Roentgenology, 182, 769–775.
Kofteridis, D.P., Tzagarakis, N., Mixaki, I., Maganas, E., Xilouri, E.,
Stathopoulos, E.N., Eliopoulos, G.D. & Gikas, A. (2004) Multicentric Castleman’s disease: prolonged remission with anti CD-20
monoclonal antibody in an HIV-infected patient. AIDS, 18, 585–
586.
Kumari, P., Schechter, G.P., Saini, N. & Benator, D.A. (2000) Successful treatment of human immunodeficiency virus-related Castleman’s disease with interferon-alpha. Clinical Infectious Diseases,
31, 602–604.
Lee, F.C. & Merchant, S.H. (2003) Alleviation of systemic manifestations of multicentric Castleman’s disease by thalidomide. American
Journal of Hematology, 73, 48–53.
Loi, S., Goldstein, D., Clezy, K., Milliken, S., Hoy, J. & Chipman, M.
(2004) Castleman’s disease and HIV infection in Australia. HIV
Medicine, 5, 157–162.
Marcelin, A.-G., Aaron, L., Mateus, C., Gyan, E., Gorin, I., Viard, J.-P.,
Calvez, V. & Dupin, N. (2003) Rituximab therapy for HIV-associated Castleman disease. Blood, 102, 2786–2788.
Marietta, M., Pozzi, S., Luppi, M., Bertesi, M., Cappi, C., Morselli, M.
& Torelli, G. (2003) Acquired haemophilia in HIV negative, HHV-8
positive multicentric Castleman’s disease: a case report. European
Journal of Haematology, 70, 181–182.
Martin, J.M., Bell, B. & Ruether, B.A. (1985) Giant lymph node
hyperplasia (Castleman’s disease) of hyaline vascular type. Clinical
heterogeneity with immunohistologic uniformity. American Journal
of Clinical Pathology, 84, 439–446.
Medveczky, M.M., Horvath, E., Lund, T. & Medveczky, P.G. (1997) In
vitro antiviral drug sensitivity of the Kaposi’s sarcoma-associated
herpesvirus. AIDS, 11, 1327–1332.
Menke, D.M. & DeWald, G.W. (2001) Lack of cytogenetic abnormalities in Castleman’s disease. Southern Medical Journal, 94, 472–474.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
15
Review
Menke, D.M., Tiemann, M., Camoriano, J.K., Chang, S.F., Madan, A.,
Chow, M., Habermann, T.M. & Parwaresch, R. (1996) Diagnosis of
Castleman’s disease by identification of an immunophenotypically
aberrant population of mantle zone B lymphocytes in paraffinembedded lymph node biopsies. American Journal of Clinical
Pathology, 105, 268–276.
Menke, D.M., Isaacson, P.G. & Boshoff, C. (2000) Ly-1b cells and
Castleman disease. Blood, 96, 1614–1616.
Menke, D.M., Chadbum, A., Cesarman, E., Green, E., Berenson, J.,
Said, J., Tiemann, M., Parwaresch, R. & Thome, S.D. (2002) Analysis
of the human herpesvirus 8 (HHV-8) genome and HHV-8 vIL-6
expression in archival cases of castleman disease at low risk for HIV
infection. American Journal of Clinical Pathology, 117, 268–275.
Moore, D.F., Preti, A. & Tran, S.M. (1996a) Prognostic implications
following an indeterminate diagnostic work-up of lymphoma. Blood,
88 (Suppl. 1), 229a (abstract).
Moore, P.S., Boshoff, C., Weiss, R.A. & Chang, Y. (1996b) Molecular
mimicry of human cytokine and cytokine response pathway genes by
KSHV. Science, 274, 1739–1744.
Murray, P.G., Deacon, E., Young, L.S., Barletta, J.M., Mann, R.B.,
Ambinder, R.F., Rowlands, D.C., Jones, E.L., Ramsay, A.D. &
Crocker, J. (1995) Localization of Epstein–Barr virus in Castleman’s
disease by in situ hybridization and immunohistochemistry.
Hematologic Pathology, 9, 17–26.
Nakanishi, T., Sobue, I., Toyokura, Y., Nishitani, H., Kuroiwa, Y.,
Satoyoshi, E., Tsubaki, T., Igata, A. & Ozaki, Y. (1984) The CrowFukase syndrome: a study of 102 cases in Japan. Neurology, 34, 712–
720.
Newsom-Davis, T., Bower, M., Wildfire, A., Thirlwell, C., Nelson, M.,
Gazzard, B. & Stebbing, J. (2004) Resolution of AIDS-related Castleman’s disease with anti-CD20 monoclonal antibodies is associated
with declining IL-6 and TNF-alpha levels. Leukemia and Lymphoma,
45, 1939–1941.
Neyts, J. & De Clercq, E. (1997) Antiviral drug susceptibility of human
herpesvirus 8. Antimicrobial Agents and Chemotherapy, 41, 2754–
2756.
Nishi, J., Arimura, K., Utsunomiya, A., Yonezawa, S., Kawakami, K.,
Maeno, N., Ijichi, O., Ikarimoto, N., Nakata, M., Kitajima, I.,
Fukushige, T., Takamatsu, H., Miyata, K. & Maruyama, I. (1999)
Expression of vascular endothelial growth factor in sera and lymph
nodes of the plasma cell type of Castleman’s disease. British Journal
of Haematology, 104, 482–485.
Nishimoto, N., Sasai, M., Shima, Y., Nakagawa, M., Matsumoto, T.,
Shirai, T., Kishimoto, T. & Yoshizaki, K. (2000) Improvement in
Castleman’s disease by humanized anti-interleukin-6 receptor antibody therapy. Blood, 95, 56–61.
Nord, J.A. & Karter, D. (2003) Low dose interferon-alpha therapy for
HIV-associated multicentric Castleman’s disease. International
Journal of STD and AIDS, 14, 61–62.
Ohyashiki, J.H., Ohyashiki, K., Kawakubo, K., Serizawa, H., Abe, K.,
Mikata, A. & Toyama, K. (1994) Molecular genetic, cytogenetic, and
immunophenotypic analyses in Castleman’s disease of the plasma
cell type. American Journal of Clinical Pathology, 101, 290–295.
Okamoto, I., Iyonaga, K., Fujii, K., Mori, T., Yoshioka, M., Kohrogi,
H., Matsumoto, M. & Suga, M. (2003) Absence of gallium uptake in
unicentric and multicentric Castleman’s disease. Internal Medicine,
42, 735–739.
Oksenhendler, E., Duarte, M., Soulier, J., Cacoub, P., Welker, Y.,
Cadranel, J., Cazals-Hatem, D., Autran, B., Clauvel, J.P. & Raphael,
16
M. (1996) Multicentric Castleman’s disease in HIV infection: a
clinical and pathological study of 20 patients. AIDS, 10, 61–67.
Oksenhendler, E., Carcelain, G., Aoki, Y., Boulanger, E., Maillard, A.,
Clauvel, J.P. & Agbalika, F. (2000) High levels of human herpesvirus
8 viral load, human interleukin-6, interleukin-10, and C reactive
protein correlate with exacerbation of multicentric castleman disease
in HIV-infected patients. Blood, 96, 2069–2073.
Oksenhendler, E., Boulanger, E., Galicier, L., Du, M.Q., Dupin, N.,
Diss, T.C., Hamoudi, R., Daniel, M.T., Agbalika, F., Boshoff, C.,
Clauvel, J.P., Isaacson, P.G. & Meignin, V. (2002) High incidence of
Kaposi sarcoma-associated herpesvirus-related non-Hodgkin lymphoma in patients with HIV infection and multicentric Castleman
disease. Blood, 99, 2331–2336.
Parez, N., Bader-Meunier, B., Roy, C.C. & Dommergues, J.P. (1999)
Paediatric Castleman disease: report of seven cases and review of the
literature. European Journal of Pediatrics, 158, 631–637.
Parravinci, C., Corbellino, M., Paulli, M., Magrini, U., Lazzarino, M.,
Moore, P.S. & Chang, Y. (1997) Expression of a virus-derived
cytokine, KSHV vIL-6, in HIV-seronegative Castleman’s disease.
American Journal of Pathology, 151, 1517–1522.
Peterson, B.A. & Frizzera, G. (1993) Multicentric Castleman’s disease.
Seminars in Oncology, 20, 636–647.
Reddy, M.P. & Graham, M.M. (2003) FDG positron emission tomographic imaging of thoracic Castleman’s disease. Clinical Nuclear
Medicine, 28, 325–326.
Revuelta, M.P. & Nord, J.A. (1998) Successful treatment of multicentric Castleman’s disease in a patient with human immunodeficiency virus infection. Clinical Infectious Diseases, 26, 527.
Rieu, P., Droz, D., Gessain, A., Grünfeld, J-P. & Hermine, O. (1999)
Retinoic acid for treatment of multicentric Castleman’s disease. The
Lancet, 354, 1262–1263.
Salisbury, J.R. (1990) Castleman’s disease in childhood and adolescence: report of a case and review of literature. Pediatric Pathology,
10, 609–615.
Sato, K., Tsuchiya, M., Saldanha, J., Koishihara, Y., Ohsugi, Y., Kishimoto, T. & Bendig, M.M. (1993) Reshaping a human antibody to
inhibit the interleukin 6-dependent tumor cell growth. Cancer
Research, 53, 851–856.
Senanayake, S., Kelly, J., Lloyd, A., Waliuzzaman, Z., Goldstein, D. &
Rawlinson, W. (2003) Multicentric Castleman’s disease treated with
antivirals and immunosuppressants. Journal of Medical Virology, 71,
399–403.
Soubrier, M.J., Dubost, J.J. & Sauvezie, B.J. (1994) POEMS syndrome:
a study of 25 cases and a review of the literature. French Study
Group on POEMS Syndrome. American Journal of Medicine, 97,
543–553.
Soulier, J., Grollet, L., Oksenhendler, E., Cacoub, P., Cazals-Hatem, D.,
Babinet, P., d’Agay, M.F., Clauvel, J.P., Raphael, M., Degos, L.
(1995a) Kaposi’s sarcoma-associated herpesvirus-like DNA
sequences in multicentric Castleman’s disease. Blood, 86, 1276–1280.
Soulier, J., Grollet, L., Oksenhendler, E., Miclea, J.M., Cacoub, P.,
Baruchel, A., Brice, P., Clauvel, J.P., d’Agay, M.F., Raphael, M.
(1995b) Molecular analysis of clonality in Castleman’s disease.
Blood, 86, 1131–1138.
Stansby, G., Hilson, A. & Hamilton, G. (1991) Gallium scintigraphy in
the diagnosis and management of multifocal Castleman’s disease.
British Journal of Radiology, 64, 165–167.
Suda, T., Katano, H., Delsol, G., Kakiuchi, C., Nakamura, T., Shiota,
M., Sata, T., Higashihara, M. & Mori, S. (2001) HHV-8 infection
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
Review
status of AIDS-unrelated and AIDS-associated multicentric Castleman’s disease. Pathology International, 51, 671–679.
Summerfield, G.P., Taylor, W., Bellingham, A.J. & Goldsmith, H.J.
(1983) Hyaline-vascular variant of angiofollicular lymph node hyperplasia with systemic manifestations and response to corticosteroids. Journal of Clinical Pathology, 36, 1005–1011.
Weisenburger, D.D., Nathwani, B.N., Winberg, C.D. & Rappaport, H.
(1985) Multicentric angiofollicular lymph node hyperplasia: a
clinicopathologic study of 16 cases. Human Pathology, 16, 162–172.
Yamasaki, S., Iino, T., Nakamura, M., Henzan, H., Ohshima, K.,
Kikuchi, M., Otsuka, T. & Harada, M. (2003) Detection of human
herpesvirus-8 in peripheral blood mononuclear cells from adult
Japanese patients with multicentric Castleman’s disease. British
Journal of Haematology, 120, 471–477.
Yoshizaki, K., Matsuda, T., Nishimoto, N., Kuritani, T., Taeho, L.,
Aozasa, K., Nakahata, T., Kawai, H., Tagoh, H. & Komori, T. (1989)
Pathogenic significance of interleukin-6 (IL-6/BSF-2) in Castleman’s
disease. Blood, 74, 1360–1367.
Zancai, P., Cariati, R., Quaia, M., Guidoboni, M., Rizzo, S., Boiocchi,
M. & Dolcetti, R. (2004) Retinoic acid inhibits IL-6-dependent
but not constitutive STAT3 activation in Epstein–Barr virusimmortalized B lymphocytes. International Journal of Oncology, 25,
345–355.
Zietz, C., Bogner, J.R., Goebel, F.D. & Lohrs, U. (1999) An unusual
cluster of cases of Castleman’s disease during highly active antiretroviral therapy for AIDS. The New England Journal of Medicine, 340,
1923–1924.
Zoeteweij, J.P., Eyes, S.T., Orenstein, J.M., Kawamura, T., Wu, L.,
Chandran, B., Forghani, B. & Blauvelt, A. (1999) Identification and
rapid quantification of early- and late-lytic human herpesvirus 8
infection in single cells by flow cytometric analysis: characterization
of antiherpesvirus agents. Journal of Virology, 73, 5894–5902.
ª 2005 Blackwell Publishing Ltd, British Journal of Haematology, 129, 3–17
17