Determination of T lymphocyte subpopulations by monoclonal antibodies in rheumatoid arthritis. Influence of immunomodulating agents.

The pathogenesis of rheumatoid arthritis is unknown, but clear abnormalities of the immune system are well documented in this disease. We therefore evaluated T cell subpopulations in patients with rheumatoid arthritis using monoclonal antibodies previously shown to react with all T cells (OKT3), with inducer/helper T cells (OKT4) and with suppressor/cytotoxic T cells (OKT8). These investigations disclosed evidence of a significant decrease in the number of OKT8+ cells/mm3 and a high inducer-helper/suppressor-cytotoxic (OKT4+/OKT8+) ratio in active rheumatoid arthritis. A modest number of patients with active arthritis were treated wit levamisole or with synthetic thymopoietin 32-36 (thymopoietin pentapeptide or TP-5). These individuals responded with ratio decreases to more normal levels. Our data support the hypothesis that monoclonal T cell antibodies may offer an important tool for the further evaluation of patients with rheumatoid arthritis and their individual response to treatment.