Our study was undertaken to determine the phenotypic changes and cytokine production from the synovial fluid (SF) and blood of patients with rheumatoid arthritis (RA).
Blood and SF purified T cells were stained with monoclonal antibodies using standard, indirect immunofluorescence technique for the determination of T cell receptor (TcR) TcR alpha beta and TcR gamma delta antigen expressions, CD25, CD38, CD71, HLA-DR activation antigens, and for percentage distribution of CD4+CD29+ and CD4+CD45RA+ subsets. The production of interleukin 2 (IL-2), IL-4 and IL-6 by various T cell compartments was determined by the bioassay or enzyme linked immunosorbent assay methods.
Highly elevated percentage of CD3+TcR gamma delta and CD4+CD29+ T cell subsets were detected in SF and blood of RA. The CD4+CD29+ T cell subsets produced elevated levels of IL-4 and IL-6 but deficient levels of IL-2. IL-6 cytokine induced CD4+CD29+ subsets were found to provide effective helper function to B cells in IgG and IgM synthesis.
The IL-6 production and IL-6 induced CD4+CD29+ T cell subset function in B cell antibody synthesis may be important in B cell hyperactivity and antibody synthesis in RA. Our studies suggest that CD4+CD29+ subsets bearing TcR gamma delta antigens are increased at inflammation site (SF) in RA and is implicated in immunopathology and autoantibody production of this inflammatory condition in humans.