Human immunodeficiency virus (HIV)-associated myopathy: immunocytochemical identification of an HIV antigen (gp 41) in muscle macrophages.

In a patient with acquired immunodeficiency disease syndrome (AIDS) and muscle weakness, a muscle biopsy specimen disclosed degeneration of muscle fibers, regeneration, and focal endomysial mononuclear inflammation. A conspicuous feature was the presence of perivascular macrophages within the endomysium that showed positive immunostaining for human immunodeficiency virus (HIV) (gp 41) antigen. HIV was not detected within myofibers. Our findings suggest an important role for the HIV-infected macrophage in the pathogenesis of this myopathy.