Presence of human 65 kD heat shock protein (hsp) in inflamed joints and subcutaneous nodules of RA patients

Monoclonal antibodies to the human homologue of the bacterial 65 kD heat shock protein (hsp) were used to investigate the tissue distribution of endogenous hsp 65 in normal versus rheumatoid synovial tissue, in subcutaneous nodules of patients with rheumatoid arthritis (RA) and in several instances of non-rheumatoid inflammation. A strong reactivity of the anti-hsp antibody was found in the cartilage-pannus junction in rheumatoid joints and in rheumatoid nodules, but not in normal joints or in normal or inflamed kidney or liver (irreversible graft rejection, chronic glomerulonephritis or primary biliary cirrhosis). The findings provide a new hypothetical explanation for a role of T cells reactive with the 65 kD hsp in the generation of both articular and extra-articular lesions in chronic rheumatoid arthritis.