Sjogren's syndrome and polymyositis or dermatomyositis
S. P. Ringel, J. Z. Forstot, E. M. Tan, C. Wehling, R. C. Griggs and D. Butcher
Of four patients with Sjogren's syndrome, three had polymyositis and one
had dermatomyositis. In all, deposition of IgG, IgA, IgM, and C3 was
observed in muscle by immunofluorescent techniques. Serologic studies
revealed elevated levels of serum IgG and IgM, rheumatoid factor, and
antinuclear antibody with specificity for SS-A and SS-B antigens. In muscle
there was a mononuclear cell infiltrate with plasma cell predominance
around small vessels and capillaries. Ultrastructural changes in the
vessels included reduplication of the basement membrane, endothelial
thickening, and numerous tubuloreticular and dense inclusions. In two
patients, electrondense deposits were noted in the microvasculature. This
combination of immunoglobulin deposition in muscle, prominent microvascular
changes, and characteristic serology suggests that the myositis in
Sjogren's syndrome may result from small-vessel injury by autoantibodies or
circulating immune complexes.
