Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
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 fc& ^ 4JP*S* ', * •* '^JPt i tw 248 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 1. Chou SM: Myxovirus-like structures in a case of human chronic polymyositis. Science 158: 1453-1455, 1967 2. Chou SM: Myxovirus-like structures and accompanying nuclear changes in chronic polymyositis. Arch Pathol 86:649-658, 1968 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 structures. J Neuropathol Exp Neurol 26:601G19, 1967 5. Fcorino PM, Hierholzer JC, Norton WL: Viral isolation studies of inclusion positive biopsy from human connective tissue diseases. Arthritis Rheum 13:378-380, 1970 6. Grausz H, Earley LE, Stephens BG: Diagnostic import of virus-like particles in the glomerular endothelium of patients with systemic lupus erythematodcs. N Engl J Med 283:506511, 1970 7. Gyorkey F, Sinkovics J, Gyorkey P: Systemic lupus erythematodes and myxovirus. N Engl J Med 280:333-333, 1969 8. Godman GC, Bunting H, Mclnick JL: T h e histopathology of Coxsackie virus infection in mice. Am J Pathol 28:223-257, 1952 9. Haas YE, Yunis EJ: Tubular inclusions of systemic lupus erythematodes. Ultrastructural observations, regarding their possible viral nature. Exp Molec Pathol 12:257-263, 1970 10. Hurd ER, Eigenbrodt E, Ziff M: Cytoplasmic tubular structures in kidney biopsies in systemic lupus erythematodes. Arthritis Rheum 12:541-542, 1969 11. Joel EH, Eduardo JY: Viral crystalline arrays in human Coxsackie myocarditis. Lab Invest 23:442-446, 1970 12. Shearn MA, T u W H , Stephens BG: Virus-like structures in Sjogren's syndrome. Lancet 1: 568-569, 1970 13. Zwymiiller E: Schwere Haut-Muskelerkrankung timer dem Klinischen Erscheinungsbild einer Dermatomyositis mit Coxsackie-Virus befund. Dtsch Med Wochcnschr 78:190-192, 1953