Objective: To detect evidence of abnormalities of the p53 protein in autoimmune diseases. Mutation of the p53 protein may inhibit apoptosis and thereby lead to cancer and possibly play a role in the pathogenesis of autoimmune diseases.
Methods: Serum antibodies to p53 are detected in 30 to 50% of patients with cancer who have p53 mutations. Using an ELISA, we determined the prevalence of anti-p53 antibodies in the serum of 106 patients with rheumatoid arthritis (RA), 72 patients with primary Sjögren's syndrome (SS), and 14 patients with lymphoma complicating SS. The presence of anti-p53 antibodies was also measured in the synovial fluid of 16 patients with RA. Positive sera by ELISA were confirmed by immunoprecipitation.
Results: Serum anti-p53 antibodies were detected in 2 of 106 patients with RA. The synovial fluid of one of these 2 patients was also studied and was positive. Anti-p53 antibodies were not detected in the other synovial fluids. Serum anti-p53 antibodies were not detected in 72 patients with primary SS alone, but were present in 2 of 14 patients with lymphoma complicating SS.
Conclusion: Our results suggest that if p53 mutations have any role in the pathogenesis of some autoimmune diseases, they are rarely associated with the presence of anti-p53 antibodies in patients with RA. In patients with SS, the presence of serum anti-p53 antibodies might be an indirect sign of the development of a lymphoma.