Background Rheumatoid arthritis (RA) is a common autoimmune disease that is primarily driven by effector Tcells, in particular by Th17 cells which are contained within CD4+CD161+ Tcells.
Objectives We aim to evaluate the levels and cytokine secretion of circulating CD4+CD161+ T cells and Th17-related cytokines in patients with RA, and to elucidatetheir correlations with RA disease activity.
Methods Flow cytometry was used to analyze the surface phenotype and cytokine production of peripheral blood from 42 patients with RA and 11 healthy controls (HC). Plasma levels of Th17-related cytokines were measured by cytometric bead array (CBA). Additionally, disease activity was evaluated by the 28-joint Disease Activity Score (DAS28). Spearman's rank correlation and Receiver operating characteristic (ROC) curve were used for analyzing the relation of the indicators and disease activity.
Results Mainly circulating interleukin (IL)-17–producing cells were contained within the CD4+CD161+ T cells in patients with RA and HC. The levels of circulating CD4+CD161+ T cells, CD4+CD161+IL-17+IFN-γ+ cells (CD161+ Th17 cells), IL-17 and IL-6 in RA patient were significantly elevated and correlated strongly with disease activity indices. Accordingly, enhanced percentages of these indicators were observed in RA patients with active disease status (DAS28 >3.2) than in those with low disease status (DAS28 ≤3.2). In contrast, the percentages of circulating CD4+CD161+IL-17−IFN-γ+ cells (CD161+ Th1 cells) were significantly decreased and negatively correlated with disease activity indices in RA patients. ROC curve analysis identifiedthe composite indicator which was combined by the levels of CD4+CD161+ T cells and erythrocyte sedimentation rate (ESR) distinguished disease activity with 91.7% sensitivity and 94.4% specificity.
Conclusions Circulating CD4+CD161+ T cells may consider as a potentially cytologic biomarker of RA disease activity. Moreover, the composite indicator including CD4+CD161+ T cells and ESR may be a useful indicator for monitoring disease activity and treatment response in RA.
Disclosure of Interest None declared