Rheumatoid arthritis (RA) is an autoimmune disease in which T-cell activation plays a pivotal role in the induction of articular damage. CD4+/OX40+ T cells accumulate in the synovial fluid (SF) of RA patients, which suggests that they are involved in the pathogenesis of the disease. In this study, we assessed the intracellular cytokine production of peripheral blood and SF CD4+ and CD4+/OX40+ T cells from RA patients in order to evaluate their role in this disorder. Our results show that SF CD4+ cells are predominantly interferon gamma (IFN-gamma)-positive and express a Th1-like cytokine pattern. In SF, significantly more CD4+/OX40+ T cells expressed interleukin-4 (IL-4) and IL4/IFN-gamma than IFN-gamma alone. Our data demonstrate that SF CD4+/OX40+ T cells express a Th2/Th0 cytokine profile, which suggests that they are involved in inflammatory responses in RA joints.