Figure 2.

CD25⁺CD4⁺ T cells are enriched in the synovial fluid in rheumatoid arthritis. Mononuclear cells were isolated from the peripheral blood (PB) or the synovial fluid (SF) of a patient with rheumatoid arthritis, stained with monoclonal antibodies against CD4 and CD25 and analyzed by flow cytometry. The numbers denote the frequency of cells in the gate as defined by the expression of CD4 and CD25.