Download X-linked hyper IgM syndrome = CD40 ligand deficiency

#43 Immunodeficiencies II
Immunology 297
September 9, 2015
Ikuo Tsunoda, MD, Ph.D.
Department of Microbiology and Immunology
LSUHSC
E-mail: [email protected]
Homepage: http://tsunodalaboratory.web.fc2.com/
Thymic defects with additional congenital
anormalies (Table 2.3a)
•Failure of thymus to undergo normal development affects the
development of all populations of T cells
•DiGeorge syndrome, described by Dr. Angelio DiGeroge in 1968
•Deletion of region on chromosome 22 q11.2 can result in complete
absence of a thymus: can be explained by a deletion of a
transcription factor, T box-1 (TBOX1)
•The result is immunodeficiency, nearly complete T cell defect,
and lack of T cell-dependent B cell activation
•Normal level of serum immunoglobulin
•Defective development of structures that develop from the third and
fourth pharyngeal pouches during fetal life: absent parathyroid
glands, abnormal development of great vessels
Pharyngeal Pouches
https://www.youtube.com/watch?v=WiE7LJu3AL4
Pharyngeal pouches.
paired evaginations of
embryonic pharyngeal
endoderm, between the
pharyngeal arches,
extending toward the
corresponding
ectodermally lined
pharyngeal grooves;
during development
they evolve into
epithelial tissues and
organs, such as thymus
and thyroid glands.
SYN: branchial
pouches, endodermal
pouches.
DiGeorge
syndrome
•22q11.2 deletion syndrome
= velocardiofacial syndrome
= DiGeorge syndrome
Microdeletion; a submicroscopic
loss of a segment of DNA of varying
size, typically several kilobases
long
•Incidence; 1 in 2000 - 4000 live births
•Craniofacial and cardiovascular
anomalies, immunodeficiency, short
stature and hypocalcaemia
Mouse chromosome 16
•Cognitive and behavioral impairments
and a high risk for developing
schizophrenia
•Mouse models of the 22q11.2
microdeletion
DiGeorge syndrome
•Also can result in facial
abnormalities including
dysplasia of ears and mouth,
and abnormally long distance
between the eyes.
Differing phenotypes occur because
the mutation can (but does not always)
affect the development of multiple
organs:
thymus
parathyroid gland
heart outflow vessels
facial deformity
CATCH 22 syndrome: cardiac, abnormal faces, thymic
hypoplasia, cleft palate, hypocalcemia
Immune disorders involving the thymus
Nude (nu/nu) mice :
•Hairless mouse spontaneously generated in a mouse facility
•Athymic or vestigial thymus, so very few T cells.
•In both mice and humans, mutations in FOXN1 (also known as
WHN), transcription factor selectively expressed in skin and thymus
•FOXN1 is necessary for the differentiation of thymic epithelium and
the formation of a functional thymus
•B cell development is normal
Winged helix deficiency (nude)
(Table 2.9)
Nasal dystrophy, alopecia of scalp, eyebrows, eyelashes
FOX: forkhead box
The crystal structure of the
forkhead domain: “winged
box” owing to its doublewing structure like a
butterfly
SCID mouse and nude mouse
Nude mice
no thymus, B cells+, few T cells defect in
the gene for Whn, a transcription factor
required for terminal epithelial cell
differentiation, normal bone marrow
SCID mice
Defect in bone marrow, not in the thymus
Reciprocal grafts of
thymus and bone
marrow between SCID
and nude mice
Nude bone marrow
precursors develop
normal in a scid
thymus
Transplanting a scid
thymus into nude mice
leads to T-cell
development
SCID bone marrow
cannot develop T
cells, even in a wildtype recipient
Hyper IgE syndrome (HIES, Table 2.5)
•Autosomal dominant hyper-IgE recurrent infection syndrome
•Davis et al. (1966) called the disorder 'Job’s syndrome' because of phenotypic
similarity to the biblical figure Job: 'Satan...smote Job with sore boils from the sole
of his foot unto his crown' (Job 2:7)
•Defect in STAT3, which is activated downstream of IL-6 and IL-23
•Deficient Th17 differentiation
•Defective neutrophil recruitment
•Bacteria and fungal infections
http://www.omim.org/entry/147060?search=147060&highlight=147060
Epithelium
Neutrophil
Dendritic cell
http://downloads.info4pi.org/pdfs/Inmunocytes-against-Candida---The-importance-of-our-TH17-army.pdf
HIES: Hyper IgE syndrome
Table 3. Predominantly
antibody deficiency
CVID
•Immunoglobulin levels in newborn infants fall to low levels at about
6 month of age
•IgG is actively transported across the placenta from the mother
during gestation
•After birth, IgG production does not begin for 6 months
•IgG levels are low from the age of 3 months to 1 year
Endothelial
cells of fetal
capillary
Syncytiotrophoblast
Maternal
blood
Villi
to the fetal
circulation
FcRn: neonatal Fc receptor for IgG
Syncytiotrophoblasts are bathed in maternal blood and internalize
serum containing maternal IgG. FcRn is expressed in the internal
vesicles of the syncytiotrophoblast. On acidification in the
endosome, FcRn binds to maternal IgG and transcytoses it to the
fetal circulation where it is released at physiological pH.
B cell immunodeficiencies
•Encapsulated bacteria (Haemophilus influenza, Pneumococcus spp., etc..)
have polysaccharide capsules that are not bound by pattern
recognition receptors on macrophages and neutrophils, and
therefore are not phagocytosed directly
•Thus, antibody and complement are critical for binding the bacteria
and initiating opsonization.
•Antibody is also critical for some viruses, particularly those that
infect the gut (enteroviruses)
X-linked agammaglobulinemia (Table 3.1a)
•The first description of an immunodeficiency disease was by Ogden C.
Bruton (1952) in a child that failed to produce antibody
•The disease was later termed:
Bruton’s X-linked agammaglobulinemia (XLA)
•Recurrent bacterial infection, such as Streptococcus pneumoniae, and
chronic viral infections, such as hepatitis B and C, poliovirus, echovirus,
coxsackie viruses and adenovirus
Primary role for secretory IgA in host defense (T cells are normal)
•Disease is caused by a mutation in a protein tyrosine kinase important for B
cell signaling:
Btk: Bruton’s tyrosine kinase
•During the first 6 to 9 months, remain well by maternally transmitted IgG
antibodies, thereafter, repeated infections with extracellular organisms,
unless given prophylactic antibiotics or γ-globulin therapy
Btk function in B cell development
Btk signaling from the pre-B cell receptor is required for development.
CD79a, Table 3.1d
CD79β, Table 3.1e
Table 3.1a
Table 5.5b
Table 2.14
BTK gene is important for B-cell development
•In XLA male, B cell development
arrest
•In females, one of the two X
chromosomes in each cell is
permanently inactivated. Choice
of inactivation is random
•In females, each cell has one
active chromosome and one
inactive chromosome. If the
mutation is on the inactive copy,
then there is no effect.
•If the wild-type btk gene is on
inactivated chromosome, no
development. All B cells have the
normal X chromosome.
•In monocytes, equal mixture of
normal and BTK mutant X
chromosomes (BTK gene is
required only for B cell
development) in carrier
(A) Among lymphocyte-gated cells,
only CD20+ B cells are Btk+
(B) Monocytes are also Btk+, while
neutrophils are Btk-
(all) CD20+ B cells are Btk protein+
No B
cells
Btkcells
B cells and monocytes are Btk protein+
Btk+
cells
Many immunodeficiencies are X-linked
•Most gene defects in PIDs
are recessive
(Table 5.3a)
(Table 8.16)
(Table 2.1a)
(XSCID, Table 1.1a)
(Btk-, Table 3.1a)
•Many are caused by gene
mutations on the X
chromosome
•All male with defective X
chromosome gene show
the disease, as males have
only one X chromosome
•Female carriers with one
defective X chromosome
are usually healthy
(Table 3.3a, Table 1.3)
Hyper IgM syndrome (Table 3.3)
•Normal B- and T-cell development, normal or high levels of serum
IgM (as high as 10 mg/ml; normal levels are 1.5 mg/ml)
•Limited IgM antibody responses against antigens that require T-cell
help
•Produce only very low levels of other classes of antibody because
of problems with Ig class switching.
•Patients are highly susceptible to infection with extracellular
pathogens
•At least six different gene mutations cause hyper IgM syndrome
•Most common form:
X-linked hyper IgM syndrome = CD40 ligand deficiency
(Table 3.3a)
X-linked hyper IgM syndrome
•Opportunistic infection, increased risk of malignancy
•Deficiency in CD40 ligand (CD154) on activated CD4+ T cells
•Class switching and formation of
memory B cells both require contact
with CD40L on helper T cells
•B cells develop normally, but cannot
become fully activated by most antigens
•Treatment: bone marrow transplant, intravenous
Immunoglobulin (IVIG) administration
1.
2.
Antigen bound by surface immunoglobulin on
the B cell is internalized and returned to the cell
surface as peptides bound to MHC class II
Helper T cells recognize the peptide and activate
B cells via interaction between CD40L on T cells
and CD40 on B cells
•Interaction of B cells and helper T cells
leads to CD40L expression on T cells and
IL-4, 5, and 6 production, which drive the
proliferation and differentiation of B cell
into plasma cells and memory cells
•The second signal required to activate
antibody production against thymusindependent antigens is provided by
recognition of microbial constituent or by
extensive membrane IgM cross-linking
Hyper IgM syndrome
Most common form:
X-linked hyper IgM syndrome
Formation of germinal centers
requires B cell activation by helper
T cells
FIGURE 46.2 The role of the
CD40 ligand (CD154) in B cell
class switching. The CD154
gene is mutated in X-linked
hyper immunoglobulin M
(IgM) syndrome. Thus, this is
a T cell, not a B cell, defect.
IL, interleukin. (From Allen
RC, Armitage RJ, Conley ME,
et al. CD40 ligand gene
defects responsible for Xlinked hyper IgM syndrome.
Science. 1993;259:990)
Fundamental Immunology 6th
edition
Selective IgA deficiency (Table 3.4g)
•The most common inherited form of immunoglobulin deficiency :
1 in 333 reported among some blood donors
•Normal numbers of sIgA-expressing B cells, but decreased
synthesis or release of IgA
•Low serum IgA < 50 μg / ml (normal 2 to 4 mg / ml)
•Normal or elevated levels of IgM and IgG
•The absence of IgA predisposes to some types of infections
(particularly respiratory), but many with an IgA deficiency are
outwardly “normal”.
•The cause of selective IgA deficiency is unknown
•Some patients have mutations in TACI (one of the three types of
receptors for BAFF and APRIL) (Table 3.2g)
Table 4.
Diseases of
immune
dysregulation
Some deficiencies can lead to
lymphoproliferative diseases (Table 4.1)
•Familial hemophagocytic lymphohistiocytosis (FHL or FHLH) is
caused by an inherited deficiency of perforin
•Hemophagocytosis: ingestion of red blood cells by macrophages
•Pfp-/- mice infected with some types of viruses result in a disease
similar to FHL because the immune system is uncontrolled 
demonstrates that perforin plays an important role in regulating the
immune response
•Hemophagocytic lymphohistiocytosis (HLH)
=Hemophagocytic syndrome (HPS)
=Macrophage activation syndrome
•
In FHL, mutations prevent NK cells
and cytotoxic T cells from releasing
their cytoplasmic granules, which
leads to uncontrolled proliferation of
lymphocytes and macrophages
•
These cells phagocytose blood cells
and release huge amounts of
proinflammatory cytokines
•
Cytokine burst explains the
inflammation, fever and systemic
illness
•
T cell and macrophage infiltration in
liver, spleen, lymph nodes, bone
marrow, and central nervous system
•
T cells and macrophages respond
strongly to microbes to compensate
for the CTL and NK cell defects?
•
•
•
•
•
Anemia
Thrombocytopenia
Hemophagocytosis
in bone marrow,
spleen, lymph node
Increased cytokine
release: interferonγ, TNF, IL-6, IL-10,
macrophage
colony-stimulating
factor (M-CSF)
Treatment: control
the cytokine burst
by chemotherapy
and immunotherapy
with etoposide,
corticosteroids and
cyclosporine,
followed by bone
marrow
transplantation
Hemophagocytic lymphohistiocytosis (HLH)
Hemophagocytic syndrome (HPS)
Genetic hemophagocytic lymphohistiocytosis
=primary hemophagocytic syndrome
• Familial hemophagocytic lymphohistiocytosis (FHL) (Table 4.1.1)
FHL1: unidentified gene on chromosome 9
FHL2: perforin (PRF1) mutation
FHL3: Munc13-4 (UNC13D) mutation
FHL4: syntaxin 11 (STX11) mutation
FHL5: syntaxin binding protein (STXBP) 2 (Munc 18-2) mutation
All four proteins are involved in the granule-mediated
cytotoxic
pathway of lymphocytes
• FLH with hypopigmentation (Table 4.1.2)
Chediak-Higashi syndrome 1: LYST (=CHS1) mutation
Griscelli syndrome 2: RAB27A mutation
LYST and RAB27A: role in vesicle trafficking in CTL
Hermansky-Pudlak syndrome 2 (HPS2), AP3B1 mutation
• (X-linked lymphoproliferative syndrome: SH2D1A mutation)
NK cell inhibition leads to severe EB virus infection
and sustained proliferation of CTL (Table 4.2a)
Chediak-Higashi syndrome
•A defect in LYST (=CHS1), which is involved in intracelluar vesicle
formation and trafficking
•Reported by Moises Chediak (1954) and Ototaka Higashi (1956)
•A failure of lysosomes and phagosomes to fuse properly
•Phagocytes have enlarged granules and impaired intracellular
killing ability
•Partial albinism, abnormal platelet function, severe
http://www.jpeds.or.jp/saisin/saisin_100604.html
immunodeficiency
http://www.nurs.or.jp/~academy/igaku/t1/t1241.htm
Ototaka Higashi, 東音高
IPEX: immune dysregulation,
polyendocrinopathy, enteropathy, Xlinked syndrome (Table 4.3a)
•Mutations in the forkhead box P3 (FOXP3) gene on
Xp11.23
•FOXP3 is expressed on CD4+CD25+ regulatory T cells
(Tregs)
•Lack of (and/or impaired function of) CD4+CD25+ T
regs
•Fatal X-linked recessive immunologic disorder
•Multisystem autoimmunity: early onset type I diabetes
mellitus, severe enteropathy with watery, often bloody
diarrhea associated with eosinophilic inflammation and
an eczematous dermatitis
•Recurrent infections caused by Enterococcus and
Staphylococcus species
CD4+ regulatory T cells (Treg)
• Suppress effector T cells to prevent
autoimmunity
• Multiple Treg populations
• Foxp3+ Treg; FOXP3 (forkhead box P3)+,
CD4+, CD25 (IL-2 receptor α-chain)+, CTLA-4
(CD152)+, GITR (glucocorticoid-induced TNF
receptor)+, CD127 (IL-7Rα) -
Sakaguchi et al. Cell. 2008,133:775-87
FOXP3 mutations in IPEX
•Immune dysregulation; autoantibody
•Polyendocrinopathy; diabetes, thyroiditis
•Enteropathy; diarrhea (autoimmune enteropathy)
•X-linked; male patients
Scurfy mice
•Lack Foxp3 and Treg
•Scaly skin rash
•Diarrhea
•Lymphadenopathy,
lymphocytic infiltration in
organs
•Affect male mice
Sakaguchi et al. Cell. 2008,133:775-87
DEREG mice / Foxp3-DTR mice
•Foxp3+Treg express
diphtheria toxin receptor
(DTR)
•Administration of
diphtheria toxin (DT) into
mice depletes Treg
selectively
•DT administration lead
to splenomegaly,
lymphadenopathy, and
inflammation in organs
Lahl et al., J Exp Med, 2007, 204,
57-63
Mechanisms of suppression by Treg
Sakaguchi et al. Cell. 2008,133:775-87
“How many mechanisms
do regulatory T cells
need?”
Dario A. A. Vignali
Eur. J. Immunol. 2008. 38: 901–937
Case 17
Autoimmune PolyendocrinopathyCandidiasis-Ectodermal Dystrophy
(APECED)
= Autoimmune polyglandular syndrome
(APS)-1 (Table 4.4a)
Autoimmune
regulator (AIRE)
gene encodes a
transcription
factor involved in
the presentation
of tissuerestricted
antigens during Tcell development
in the thymus
Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal
Dystrophy (APECED)
= Autoimmune polyglandular syndrome (APS)-1 (Table 4.4a)
•Mutation in AIRE
•Triad: Addison disease, hypoparathyroidism, mucocutaneous
candidiasis
ALPS1A
ALPS1B
Animal Model
• The recessive lymphoproliferation (lpr) phenotype and the
generalized lymphoproliferative disease (gld) phenotype are
mouse models of aberrant T-cell accumulation
• In lpr mice, a splicing defect in the Fas gene results in greatly
decreased expression of Fas.
• In gld mice, a point mutation in the C terminus of Fasl impairs its
ability to interact successfully with its receptor
• These mutations lead to a failure of apoptosis and complex
immune disorders in lpr and gld mutant mice that are analogous to
the human disorders ALPS1A and ALPS1B.
Table 5.
Congenital
defects of
phagocyte
number,
function or both
OMIM# 601604
MSMD: Mendelian
susceptibility to
mycobacterial
disease
Immunodeficiencies of phagocytic cells
Phagocyte immunodeficiencies can be grouped into 4 types:
1. Table 5.1. Defect of neutrophil function
» Phagocyte number↓ (neutropenia):
Development defect in gene required for
myeloid progenitor cell differentiation
2. Table 5.2. Defects of motility
» Phagocyte adhesion ↓
3. Table 5.3. Defects of respiratory burst
» Killing ↓
4. Table 5.4. Mendelian susceptibility to
mycobacterial disease (MSMD)
» Interferon-γ signaling pathway ↓: susceptibility
to Mycobacteria and Salmonella
Leukocyte adhesion deficiency (LAD) (Table 5.2)
•The most significant problem is the inability of cells to attach to the vascular
endothelium and migrate to sites of inflammation
•LAD type 1 (LAD-1): deficient expression of β2 integrins due to CD18 gene mutations
•LAD type 2 (LAD-2): absence of sialyl Lewis X: ligand on neutrophils required for
binding to E-selectin and P-selectin on endothelium [Caused by FUCT1 (fucose
transporter gene) mutation: the failure to transport fucose into the Golgi complex
results in failure to synthesize sialyl Lewis X]
•LAD type 3, deficiency of Kindlin-3, required for firm adhesion
LAD type 1
•Leukocyte adhesion deficiency (LAD) results from mutation in the
CD18 molecule – the b2 chain of the integrin family
•The result is a loss of surface expression of key integrin molecules:
Abnormal functions: endothelium adherence, neutrophil chemotaxis,
phagocytosis, cytotoxicity
Mac-1
p150:95
Defects in phagocytic cells are associated with
persistence of bacterial infection
5.1: Defects of
neutrophil
differentiation
5.2: Defects of
motility
LAD
6.2a, b: IRAK4,
MyD88
deficiency
5.3: Defects of
respiratory
burst
CGD
Table 4.1.2: FLH syndromes with
hypopigmentation
Autoinflammatory diseases are
clinical disorders marked by
abnormally increased
inflammation, mediated
predominantly by the cells and
molecules of the innate immune
system, with a significant host
predisposition.
Complement deficiencies
Defects in
elimination of
apoptotic cells,
associated
with SLE
MBL:mannose-binding
lectin
Defects in the
membrane-attack
components are
associated only with
Neisseria infections
(meningitis, gonorrhea)
=
http://tsunodalaboratory.blog.fc2.com/blog-entry-155.html
We have added a new category
in Table 9 in which
“Phenocopies of PID” are
listed. This has resulted from
our understanding and study
of conditions that present as
inherited immunodeficiencies,
but which are not due to
germline mutations and instead
arise from acquired
mechanisms. Examples
include somatic mutations in
specific immune cell
populations that give rise to
the phenotype of autoimmune
lymphoproliferative syndrome
(ALPS), and also
autoantibodies against specific
cytokines or immunological
factors, with depletion of these
factors leading to
immunodeficiency.
Therapeutic approaches for PIDs
•Two aims
•Minimize and control infections
•Replace the defective or absent components of the immune
system by adoptive transfer or transplantation
•Passive immunization with pooled gamma globulin
•X-linked agammaglobulinemia
•Bone marrow transplantation
•SCID with ADA deficiency, Wiskott-Aldrich syndrome, bare
lymphocyte syndrome, LAD
•T cell depletion from bone marrow and HLA matching to prevent
graft-versus-host disease
•Enzyme replacement therapy
•ADA and PNP deficiency
•Bovine ADA conjugated to polyethylene glycol to prolong its
serum half-life
•Gene replacement
•Difficulties in purifying self-renewing stem cells (ideal target)
•Lack of method for introducing genes into cells to achieve
stable, long-lived, and high-level expression
Bone marrow donor and recipient
must share at least some MHC
molecules to restore immune
function
•Major difficulties in bone marrow
transplantation result from MHC
polymorphism
•MHC alleles expressed by the thymic
epithelium determine which T cells can
be positively selected
•T cells and antigen presenting cells are
derived from the graft
GVHD and HVGD in bone marrow transplantation
•GVHD: Mature T cells from graft can attack host cells by recognizing their
MHC antigen
•This can be prevented by T-cell depletion of the donor bone marrow
•HVGD: if the recipient has competent T cells, these can attack the bone
marrow cells, causing transplant rejection
•Bone marrow recipients are treated with irradiation that kills their own
lymphocytes, thus making space for the grafted bone marrow of mature
T cells, and minimizing the threat of HVGD
•There is little problem in SCID patients because of immunodeficiency
Questions
X-lined hyper IgM syndrome is caused by a defect in T cells, but not in B cells.
Explain this hyper IgM syndrome with a figure showing an interaction between B cells
and T cells, and using patients’ data below
Flow cyotmetry can be useful for detection of
X-lined agammaglobulinemia patients and
carriers. Explain this flow cytometric
analyses of (A) dot plots of CD20 and
Bruton’s tyrosine kinase (Btk) expression in
lymphocyte-gated cells and (B) histograms
of Btk expression in CD14+ monocytes from
normal control (top), a male patient (middle)
and his mother (bottom).
Questions
Explain genetic mutations and immunodeficiencies in SCID and nude mice and
compare and contrast these two immunodeficient mice ( in the Exam, I recommend
using the following figure
?
?
?
?
Explain immunopathology of hemophagocytic lymphohistiocytosis (FHL or FHLH,
hemophagocytic syndrome, HPS), using the following key words: perforin, anemia,
macrophages, cytokines
CD19 is expressed from pre-B cells until the terminal differentiation to plasma cells
BTK(+) B cells?
BTK(-) pre-B cells?
All B cells in carrier
should be Btk+?