Antibodies to 65 kDa and 70 kDa heat shock proteins in rheumatoid arthritis and systemic lupus erythematosus.

To test the potential role of autoimmunity to the highly conserved heat shock proteins (HSP) in immune arthritides, the sera from 99 patients with rheumatoid arthritis (RA), 48 patients with systemic lupus erythematosus (SLE) and 65 normal controls were examined by ELISA for IgG and IgM antibodies to the 65 kDa and 70 kDa heat shock proteins from Mycobacterium bovis (Bacille Calmette-Guerin; BCG). In RA sera there are significant numbers of individuals with increased IgM anti-65 kDa and anti-BCG reactivity as well as IgG anti-70 kDa when compared with controls. In SLE both IgM and IgG anti-BCG, together with IgM anti-65 kDa, differed significantly from controls. The results were compared with previous reports in similar groups of patients, and it is clear that no consistent pattern of reactivity emerges. While further work may be justified looking carefully at the disease duration and other subsets of both RA and SLE, it is difficult at this stage to conclude that antibodies to autologous HSP that cross-react with mycobacterial HSP play a major role in disease pathogenesis.