['To determine whether the percentages of major CD4+CD161+ T-cell subsets [T-helper (Th)17, Th1, and Th17/Th1] in peripheral blood are correlated with disease activity of rheumatoid arthritis (RA).', 'In 42 RA patients and 15 healthy controls (HCs), the percentages of interleukin (IL)-17- and/or interferon (IFN)-γ-producing CD4+CD161+ T cells and the plasma levels of related cytokines were assessed by flow cytometry and cytometric bead array (CBA) analysis, respectively. Disease activity was evaluated by the 28-joint Disease Activity Score (DAS28).', 'The percentage of circulating CD4+CD161+IL-17+IFN-γ- T cells (CD161+ Th17) in RA patients increased significantly and was higher in patients with active disease status (DAS28 > 3.2) compared with those with low disease status (DAS28 ≤ 3.2), and correlated positively with DAS28, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), IL-17, and IL-6 levels in RA patients. The percentage of circulating CD4+CD161+IL-17-IFN-γ+ T cells (CD161+ Th1) decreased and correlated negatively with DAS28, CRP, and ESR levels in RA patients, while the percentage of CD4+CD161+IL-17+IFN-γ+ T cells (CD161+ Th17/Th1) was unchanged in RA patients and was not correlated with RA disease activity.'] Are circulating Th17 and Th1 cells expressing CD161 associated with disease activity in rheumatoid arthritis?