Download Picornavirus-like Structures in Acute Dermatomyositis

Picornavirus-like Structures in
Acute Dermatomyositis
M. BEN-BASSAT, M.D.,
AND I. MACHTEY,
M.D.
J. Casper Department of Pathology, Beilinson Hospital, Department of
Medicine and Rheumatology Clinic, Hasharon Hospital, Petah-Tiqva,
Tel-Aviv University Medical School, Tel-Aviv, Israel
Internal
and
ABSTRACT
Ben-Bassat, M., and Machtey, I: Picornavirus-like structures in acute dermatomyositis. Am. J. Clin. Pathol. 58: 245-249, 1972. A case of acute fatal dermatomyositis occurring in a young girl is described. Clinically, there was pronounced involvement of the striated muscles, skin, and brain. The patient
died 11 weeks after acute symptoms began. Histologically, there was a marked
myositis, with atrophy of muscle fibers, myolysis, and mononuclear infiltrates.
Examination with the electron microscope revealed many intracytoplasmic
crystal-like structures which closely resembled some of the picornaviruses.
This finding may be a further contribution to the concept of the viral etiology
of connective tissue diseases.
has been focused recently on
the possible etiologic role of viruses in
various connective tissue ("collagen") diseases.5-7' "•10'12 Recent reports of virus-like
particles in the muscle cells of patients suffering from polymyositis indicate that a
virus may be the etiologic agent of this disease.1-3 In the following case of acute
dermatomyositis, picornavirus-like crystals
were found in the skeletal muscle cells.
ATTENTION
Report of a Case
A 12-year-old girl was hospitalized because of fever, myalgia, rash, alopecia, and
stomatitis. The acute symptoms had begun
3 weeks prior to admission. When first seen,
she had the typical signs of dermatomyositis (DMS): there was a heliotrope rash on
her face, forehead, and upper chest, and a
macular rash on her palms. The eyelids
were swollen. There was severe myalgia involving the muscles of the shoulder and
Received June 24, 1971; received revised manuscript August 30, 1971; accepted for publication
September 16, 1971.
245
hip-girdle, as well as dysphagia. The patient was unable to lift her arms or to sit
up in bed. Body temperature was 38.4 C.
Laboratory findings were consistent with
the clinical diagnosis of dermatomyositis:
SGOT 300 units, lactic dehydrogenase 370
units, creatine phosphokinase 15 units (normal value in this laboratory is as high as
3 units), urinary creatine excretion 520 nig.
per 24 hr. The electromyogram showed the
pattern of a proximal myositis. Immunofluorescent examination revealed an antinuclear factor in her serum. No lupus erythematosus cells were found.
Initially, the patient showed mild improvement while being treated with corticosteroids, but soon her condition began to
deteriorate progressively. She became unconscious, with periods of apnea, disturbances of cardiac rhythm, and intestinal
bleeding. She died 11 weeks after onset of
the acute illness.
The autopsy and the histologic examination confirmed the clinical diagnosis of
dermatomyositis. There was extensive in-
246
BEN-BASSAT AND MACHTEY
A.J.C.P.—Vol. 5S
FIG. 1 (left). Extensive degeneration and loss of muscle fibers, interstitial fibrosis, and proliferation of sarcolemmal nuclei. Hematoxylin and eosin. X 100.
Fie. 2 (right). Muscle fibers with focal mononuclear cell infiltrate. Hematoxylin and eosin.
X200.
volvement of the skeletal muscles and of
the striated muscles of the esophagus and
diaphragm. Microscopically the muscles
showed swelling and degeneration of the
fibers, with a loss of the myofibrillar pattern, atrophy, myolysis, and proliferation
of the sarcolemmal nuclei (Fig. 1). There
was a focal infiltration, mainly perivascular, consisting of lymphocytes and plasma
cells (Fig. 2), as well as marked variability
in the transverse diameters of the muscle
fibers. Small and medium-sized arteries
showed marked intimal thickening with
narrowing of the lumen. Grossly, the brain
was edematous. Microscopic examination
revealed encephalitis with degenerative
changes of the neurons of the gray substance, proliferation of neuroglial cells, and
a mononuclear cell infiltrate, mainly perivascular.
Small segments of skeletal muscles were
taken at the time of autopsy, fixed in glutaraldehyde and osmium tetroxide, and embedded in epoxy resin. T h i n sections (1 ju,)
of the epon blocks were screened by light
microscopy, and only longitudinally cut
muscle fibers were used for ultrasections.
These were stained with lead citrate and
uranyl acetate and studied with a Philips
300 electron microscope.
Electron microscopic examination revealed numerous dense, intracytoplasmic
aggregates, located mainly in the subsarcolemmal spaces and around the nuclei of the
myocytes, but not in the muscle cell nuclei. These aggregates occurred as large
Fie. 3 (upper). Longitudinal section of a muscle cell, showing several irregular aggregates
(arrows) consisting of particles in crystalline array and surrounded by an electron-lucent zone in
the sarcoplasm near damaged mitochondria (M). T h e Z bands (Z) are well preserved. X 25,000.
FIG. 4 (lower). Crystal-like aggregate of dense particles in the interfibrillary space of a muscle
cell. T h e longitudinally cut myofibrils are relatively well preserved, with distinct Z bands (Z).
X 33,500.
Seplember
1972
247
VIRUS-LIKE STRUCTURES IN DERMATOMYOSITIS
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BEN-BASSAT AND MACHTEY
clusters of irregular shape and size (Fig. 3),
and in some sections they were surrounded
by an electron-lucent zone. Higher magnifications (as high as X 20,000) revealed that
these aggregates had a regular structure of
crystalline-like arrays and were composed
of identical dense subunits (Figs. 3 and 4)
with an average diameter of 150 to 200 A,
some of which were arranged in parallel
rows. In favorable sections, these subunit
particles showed a symmetrical arrangement of a hexagonal or triangular pattern
(Fig. 5). The particles had a high electron
density which was clearly apparent not only
after double staining (with uranyl and
lead) but also in sections stained with
uranyl acetate only.
Discussion
All the available evidence indicates that
the inclusions found in this case of acute
dermatomyositis associated with encephalitis can be regarded as viral structures. Although our conclusions are necessarily limited because no tissue was available for isolation and culture of the agent and it was
not possible to perform virologic studies to
prove a viral origin, we identified these
structures as virus-like particles on the
basis of their typical morphologic appearance. Here it should be noted that the
differentiation of such virus-like particles
from glycogen aggregates and from crosssections through Z-disks has presented difficulties. T o demonstrate that the dense particles appearing in our electron micrographs were not glycogen, we utilized the
staining properties of glycogen. Glycogen
particles have a natural low density and
do not stain with uranyl, but if the sections
are stained with lead ions, the glycogen is
more intensively stained, and this is helpful
in its identification. In contrast, the viral
particles showed high electron density in
the sections which we stained with uranyl
A.J.C.P.—Vol.
58
acetate only. Furthermore, glycogen aggregates have a pathognomonic rosette-like appearance, unlike the virus particles, which
have a striking tendency to be arranged
in orderly crystalline arrays, as is seen in
our electron micrographs. As for the resemblance of cross-sections through Z-disks
to crystal-like virus particles, it must be
noted that the Z-disks show a tetragonal
arrangement of filaments and have a woven
appearance. 4 In the case presented here,
the observation of the viral particles in
longitudinal sections together with wellpreserved Z-disks, the electron-lucent zone
surrounding the crystalline arrays, and the
arrangement of the subunit particles in a
triangular or hexagonal pattern, all argue
against the possibility that these are crosssectioned Z-disks. The ultrastructural characteristics of these crystal-like particles and
their size, location, and form are identical
to those of viruses in the RNA-picornavirus
group, and we suggest that they belong to
the Coxsackie type. The latter is known to
be associated with myositis and encephalitis
both in animal experiments 8 and in human
studies. 3 -" Notable are the reported findings of Coxsackie-like viruses in cases of
acute and subacute myositis, as compared
with those of myxovirus-like structures in
cases of chronic polymyositis,1-2 which point
to a possible relationship between the type
of virus and clinical course of the disease.3
Until now, there have been only a few reports of subacute polymyositis in which
Coxsackie-like viruses were found. 3 - 13
The finding of virus-like structures in
this case supports the new concept of a
viral etiology of dermatomyositis in particular and of the "collagen" diseases in
general. Further studies are necesary, however, to elucidate the significance of these
findings.
Acknowledgment.
Professor Alexander Colin,
Head of the Department of Biophysics, the Israel
Institute of Biological Research, Ness-Ziona, assisted in identifying the viral structures.
September 1972
VIRUS-LIKE STRUCTURES IN DERMATOMYOSITIS
249
Fie. 5. Higher magnification, showing the round profiles of the particles which are arranged in
triangular or hexagonal patterns in the crystal. X 80,000. (Inset: X 160,000.)
References
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of human chronic polymyositis. Science 158:
1453-1455, 1967
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3. Chou SM, Gutmann L: Picornavirus-like crystals in subacute polymyositis. Neurology (Minneap) 20:205-213, 1970
4. Engel AG, Gomez MR: Nemaline (Z disk) myopathy: Observations on the origin, structure
and solubility properties of the nemaline
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