Rheumatic disease sera reactive with capillaries in the mouse kidney

With an immunofluorescent technic using tissue sections of mouse kidney as substrate, sera from patients with rheumatic diseases reacted with glomerular and peritubular capillaries. The reactive factor in sera was shown to be IgG and was able to fix complement in the reaction. Capillary reactivity was frequently detected in rheumatic diseases associated with vascular lesions of undetermined etiology such as dermatopolymyositis, scleroderma, polymyalgia and temporal arteritis. It was present in lower incidence in other rheumatic diseases and in normal populations.