Expression of heat shock protein on lymphocytes in peripheral blood and synovial fluid from patients with rheumatoid arthritis.

OBJECTIVE: To determine whether heat shock proteins (HSP) are expressed on the surface of peripheral blood (PB) lymphocytes and synovial fluid (SF) lymphocytes from patients with rheumatoid arthritis (RA).
METHODS: Immunoprecipitation and flow cytometric analyses using anti-Yersinia enterocolitica HSP60 monoclonal antibodies (Mab) were performed. Phenotypes of surface HSP-positive lymphocytes were analyzed further by 2 color flow cytometry.
RESULTS: Anti-Y. enterocolitica HSP60 Mab immunoprecipitated 120, 97, 70, 60, 55, and 50 kDa proteins in extracts of healthy donor PB lymphocytes and of Daudi cells after thermal shock. Among these proteins, the 60 kDa HSP showed the greatest degree of precipitation. Surface HSP-positive lymphocytes were detected in 2 of 16 PB and 1 of 12 SF lymphocyte samples. Longitudinal studies indicated that HSP were expressed on the surface of lymphocytes in the active stage, but not in the improvement stage of the disease. Surface HSP-positive lymphocytes were mainly either [gamma delta +] T cells or [CD19+] B cells.
CONCLUSION: HSP were expressed on the surface of PB and SF lymphocytes from patients with RA. Surface HSP-positive lymphocytes might be recognized by lymphocytes since HSP are strongly immunogenic.