Analysis of T cell subsets in the peripheral blood and synovial fluid of patients with rheumatoid arthritis by means of monoclonal antibodies.

In an attempt to define the immunoregulatory mechanisms operating in rheumatoid arthritis we have enumerated T cell subsets in the peripheral blood and synovial fluid of patients with this disease. The peripheral blood analysis revealed an elevation of the ratio of inducer T cells (OKT4 positive) to suppressor/cytotoxic T cells (OKT5 positive) in patients with clinically active rheumatoid arthritis when compared with normal persons. This was due to a reduction in the percentage of suppressor/cytotoxic T lymphocytes in these patients. The synovial fluid in rheumatoid arthritis differed from the peripheral blood in 2 respects. Firstly, synovial fluid was characterised by a lower helper: suppressor ratio due to an increased number of suppressor/cytotoxic cells, and, secondly, it contained an increased number of activated T cells bearing HLA DR antigens. The majority of these activated T cells belonged to the helper/inducer T cell subset.