Polymyositis--an immunofluorescence study on the distribution of collagen types.

Type-specific antibodies to the polymorphic types of collagen have been used to study their distribution in polymyositis. Dramatic increases were observed in the staining with antibodies to Type III collagen and, to a lesser extent, with antibodies to Types I, IV, and V. The changes in capillary and endomysial basement membrane collagens (Types IV and V) as well as the proliferation of perimysial Type III collagen are discussed in relation to the muscle atrophy observed during the disease.