Expression of 65‐kd heat shock proteins in the inflammatory myopathies

In normal muscle, 65‐kd heat shock proteins (hsp) were detected on capillary endothelial cells, the mural elements of larger vessels, and some intracellular organelles, probably mitochondria. In the inflammatory myopathies, the 65‐kd hsp were detected on inflammatory cells, degenerating and regenerating fibers, and on many but not all nonnecrotic muscle fibers invaded by T cells. The expression of the 65‐kd hsp may be an immunenonspecific response to cellular “stress” but hsp determinants could possibly also serve as autoantigen(s) recognized by autoreactive T cells.