Increased gene expression of CCR6 and RORγt in peripheral blood cells of rheumatoid arthritis patients and their correlation with anti-cyclic citrullinated peptide and disease activity.

Abstract

The significance of T helper 17 (Th17) cells in the pathogenesis of rheumatoid arthritis (RA) has recently been demonstrated in many studies. Retinoic acid receptor-related orphan receptor γt (RORγt) is a transcription factor that is specifically involved in the generation of Th17 cells. Besides, the chemokine receptor CCR6, the receptor for CCL20, is characteristically expressed by these cells. Considering the pivotal roles of Th17 cells in RA pathogenesis, in this study, we assessed the gene expression of CCR6 and RORγt in the peripheral blood leukocytes of new case RA patients. Also, we evaluated their association with anticyclic citrullinated peptide (anti-CCP) antibodies and disease activity. Forty-five new case RA patients and 45 healthy persons have been recruited in this investigation. The gene expression of CCR6 and RORγt was evaluated by quantitative real-time PCR (qRT-PCR), and anti-CCP antibodies plasma levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Disease activity was measured according to the disease activity score-28 (DAS-28) formula. The gene expression of CCR6 and RORγt increased remarkably in new case RA patients compared to healthy controls (p < .05 and p < .01, respectively). Moreover, there was a positive correlation between RORγt gene expression and parameters, including gene expression of CCR6 (p = .001, r = .461), plasma levels of CCL20 (p = .0009, r = .477), ESR (p = .004, r = .419), DAS-28 (p = .006, r = .402), anti-CCP (p = .019, r = .346), and RF (p = .001, r = .451). Also, CCR6 gene expression was positively associated with the DAS-28 (p = .037, r = .310), plasma levels of anti-CCP (p = .037, r = .312), and ESR (p = .029, r = .327). Increased gene expression of CCR6 and RORγt in peripheral blood leukocytes of new case RA patients may contribute to the exacerbation and pathogenesis of RA.