In situ localization of lymphocyte subsets in synovial membranes of patients with rheumatoid arthritis with monoclonal antibodies.

Immunological analysis of the mononuclear infiltrates in 12 rheumatoid synovial membranes was performed by means of modified peroxidase antiperoxidase technique using a panel of monoclonal antibodies, directed against T cell differentiation antigens and HLA-DR (Ia-like) antigens. Helper/inducer T lymphocytes (OKT4 +, Leu3a+) were found in large numbers in nodular lymphoplasmocellular infiltrates, whereas the number of cytotoxic/suppressor T lymphocytes (OKT8 +m Leu2a+) was very low, resulting in a high T4/T8 or Leu3a/Leu2a ratio (6á14:1). In diffusely localized lymphoplasmocellular infiltrates this ratio was only slightly increased as compared with the peripheral blood of patients with rheumatoid arthritis (2á4:1). Moreover, most of these T lymphocytes appeared to have Ia-like antigens and seemed to have contact with HLA-DR+, sometimes weakly OKT6+ dendritic nonlymphoid cells. The results showed a constant basic localization pattern of T lymphocyte subsets and suggest that interactions between dendritic nonlymphoid cells, T lymphocyte subsets and B lymphocytes determine the ultimate architecture of the inflammatory infiltrates in the rheumatoid synovial membrane.