Immunohistochemical studies of interleukin-2 and gamma-interferon in rheumatoid arthritis.

Synovial tissues were studied, using immunofluorescence techniques, for localization of lymphocytic infiltrates and immune reactants, including C3, C5b-9, C9, and Ia antigen. Tissue distribution of interleukin-2 (IL-2) and gamma-interferon was also determined, using mouse monoclonal antibodies. IL-2 was found in association with OKT8 and OKT4 T cells, and gamma-interferon was noted in association with T cells, B cells, and macrophages. Staining both for IL-2 and for gamma-interferon was surprisingly faint in view of the intensity of lymphocytic infiltration.