Evaluation of T cell subsets with monoclonal antibodies in synovial fluid in rheumatoid arthritis.

Monoclonal antibodies that react with all T cells (OKT3), the inducer-helper T cell subset (OKT4), and the suppressor-cytotoxic T cell subset (OKT8) have been used to evaluate T cell and T cell subpopulations in synovial fluid (SF) from patients with rheumatoid arthritis (RA). We found that the immunoregulatory ratio of SF lymphocytes ranged from normal values to extremely low values indicating normal to excess numbers of OKT8+ cells. The rheumatoid synovium in patients with RA is characterized by the presence of lymphoid aggregates in which HLA-DR+ interdigitating cells form close contacts with a large number of OKT4+ T cells, while the OKT8+ T cells are sparse. It may be that the localizing mechanisms for OKT8+ suppressor cells in lymphoid aggregates are deficient in RA and the cells are thus permitted to pass into synovial exudates, resulting in an increase of OKT8+ cells in the SF.