Objective: To investigate the production of type II collagen (CII) antibodies in the synovial fluid (SF) of rheumatoid arthritis (RA) patients, and to examine the HLA dependence of this local production.
Methods: The ELISPOT method was used for enumerating anti-CII-reactive cells. Serologic tissue typing was performed.
Results: Anti-CII-reactive cells were found in the SF of 16 of 31 patients, but not in any of the peripheral blood samples obtained in parallel. SF anti-CII antibody production showed no correlation with clinical parameters, but its frequency increased significantly with age. The IgG anti-CII response occurred exclusively in patients who were positive for HLA-DR4 and was significantly associated with DR4.
Conclusion: Anti-CII production may be important in local immune complex formation. The indirect demonstration of a DR4-restricted T cell response to CII is an indication of a pathogenetic role of collagen autoimmunity in RA.