DERMATOMYOSITIS: MORPHOLOGICAL OBSERVATIONS AND THE INCIDENCE OF HL-A 8 ANTIGEN

Twelve children, 6M and 6F, aged 6-14 years, two with inactive disease, were studied. EKG abnormalities had been present in 5/12 and 6/12 had reflux of swallowed barium into the pyriform sinuses. In the active phase, muscle enzymes and electromyography were abnormal in all. Muscle biopsy demonstrated a round cell infiltrate (7/11) and focal sarcoleinnal stain for IgG, IgA and IgM (rarely B1C) in 3/3. Concurrent renal and skin biopsies were done in 4. Minimal deposition of IgG and B1C was seen in the glomerular stalk in ¾, while basement membrane deposition of IgG and IgE was found in ¼. On electronmicroscopy, reticular tubular arrays (RTA) were seen in glomerular endothelial cells and in dermal and muscle capillaries. None were found in the inactive case. Skin biopsy displayed diffuse dermal stain for IgG in 4/6 active cases and none in the inactive ones (2). Increases in serum immunoglobulins were present in 5/12 and elevated nitroblue tetrazolium tests in 6/12. Tissue typing identified HL-A 8 in 7/10. This data indicates that immunological studies and the presence of RTA may reflect disease activity and that HL-A 8 occurs with unusual frequency in this disease. Supported by Grant 5-M01-RR00199 and PHS AM 14218-04.