Autoantibodies to the heat-shock protein hsp73 in localized scleroderma.

We determined the presence of antibodies to the heat-shock protein hsp73 (anti-hsp73) in 57 serum samples from patients with localized scleroderma using an enzyme-linked immunosorbent assay (ELISA). In addition, 30 samples from healthy individuals, 30 from patients with systemic lupus erythematosus (SLE) and 32 from patients with systemic sclerosis were assessed. IgG and/or IgM anti-hsp73 antibodies were detected in 33% (19/57) of the patients with localized scleroderma. Among the three subtypes of localized scleroderma, generalized morphoea showed the highest incidence of anti-hsp73 antibodies (40%, 6/15). IgG and/or IgM anti-hsp73 antibodies were also detected in 9/30 samples (30%) from patients with SLE and in 13/32 samples (41%) from patients with systemic sclerosis, while the samples from the healthy controls were all negative for anti-hsp73. By immunoblotting, specific binding of antibodies to hsp73 was confirmed with representative serum samples that were positive for anti-hsp73 in the ELISA. Our findings indicate that the presence of anti-hsp73 is an additional immunological abnormality in localized scleroderma.