The Th17, Th1 and dual Th17/Th1 cells are important players in rheumatoid arthritis (RA) disease. To assess their roles, the frequency and impact of these cells were investigated in patients with different disease activity. In 14 new cases and 41 established RA patients in comparison with 22 healthy controls, the percentages of Th17, Th1 and dual Th17/Th1 cells were determined by flow-cytometry and their correlations were investigated with disease activity score (DAS28). Moreover, serum levels of IL-6 and IL-17 as inducer and functional cytokines for Th17 were investigated. Finally, serum levels of anti citrullinated protein antibody (ACPA) and rheumatoid factor (RF) were assessed. Percentage of Th17 cells in RA patients were increased in comparison with healthy controls (p<0.01). In correlation with this finding, IL-17 and IL-6 cytokines in RA patients also increased (p<0.01). The Th1 cells in RA patients were less than healthy group (p<0.05) and showed negative correlation with disease activity (r=-0.328, p<0.01). Dual Th17/Th1 cell only in new cases of RA were more than healthy control groups (p<0.01). The Th1/Th17 ratio in RA patients is statistically different with healthy control group (p<0.01) and it has negative correlation with disease activity (r=-264, p<0.05). The levels of ACPA and RF were increased with disease progression. Decreasing of Th1/Th17 ratio in RA patient suggested a new paradigm in the field of autoimmune disease and indicated that imbalance or plasticity between these subsets can be important in progress, diagnosis and therapy of RA disease.
Keywords: Rheumatoid arthritis; Th1 cells; Th17 cells.