Type II collagen-induced autoimmune otospongiosis. A preliminary report.

Otospongiosis-like lesions were induced in rats by immunizing them with native type II collagen. Immunized rats had antibody responses specific for native type II collagen and developed otospongiosis-like lesions. The spongiotic lesion was characterized by numerous osteocytes and osteoblasts in the vascular spaces and by dark staining probably due to the chemical alteration of ground substances. Bone resorption and new bone formation were clearly visible. Immunofluorescence studies demonstrated deposition of immunoglobulin and complement on the bone matrix and wall within the area of spongiosis. An antibody-mediated etiopathogenesis was suspected.