LOCAL ANTI-TYPE-II COLLAGEN ANTIBODY-PRODUCTION IN RHEUMATOID-ARTHRITIS SYNOVIAL-FLUID - EVIDENCE FOR AN HLA-DRL-RESTRICTED IGG RESPONSE

Objective. To investigate the production of type II collagen (CII) ant ibodies in the synovial fluid (SF) of rheumatoid arthritis (RA) patien ts, and to examine the HLA dependence of this local production. Method s. The ELISPOT method was used for enumerating anti-CII-reactive cells . Serologic tissue typing was performed. Results. Anti-CII-reactive ce lls were found in the SF of 16 of 31 patients, but not in any of the p eripheral blood samples obtained in parallel. SF anti-CII antibody pro duction showed no correlation with clinical parameters, but its freque ncy increased significantly with age. The IgG anti-CII response occurr ed exclusively in patients who were positive for HLA-DR4 and was signi ficantly associated with DR4. Conclusion. Anti-CII production may be i mportant in local immune complex formation. The indirect demonstration of a DR4-restricted T cell response to CII is an indication of a path ogenetic role of collagen autoimmunity in RA.