(a) Example of diverse pattern of response to antigens. Bars indicate mean proliferation and standard deviations of triplicate values. T cell proliferative responses were judged to be different between the synovial fluid and peripheral blood compartments if the standard deviations of the mean value of proliferation to an antigen in the synovial fluid compartment did not overlap with the standard deviations of the mean value of proliferation to the same antigen in the peripheral blood compartment. (b) The proliferative responses to SLO and TT observed in the patients in the diverse group (n = 17). Responses in the peripheral blood differed significantly to those in the synovial fluid (SLO, P = 0.0002; TT, P = 0.0002). CPM, counts per minute; PBMC, peripheral blood mononuclear cells; SFMC, synovial fluid mononuclear cells.