The TH17/Treg Imbalance in Rheumatoid Arthritis and Relation to Disease Activity

Objectives: T regulatory cells (Treg) and proinflammatory TH17 cells are newly identified T lymphocyte subsets, which have significant effects on autoimmunity and inflammation. Tregs play key role in the maintenance of self-tolerance. TH17/Treg disturbed balance has been reported to contribute to several autoimmune diseases.Our aim was to assess the Treg/TH17 pattern and TH17 related cytokines, in peripheral blood of Egyptian rheumatoid arthritis patients, and their relation to disease activity score (DAS). Analyzing IL17A and IL23 as indicators of TH17 function, was to study the effect of TH17 in RA.Methods: 100 Egyptian rheumatoid arthritis patients, divided into Group I (14), Group II (48), Group III (38), with low 5.1, activity DAS score respectively; and 50 healthy age and sex matched controls were enrolled. Peripheral blood TH17 and Treg (CD4+CD25+Foxp3+) frequencies were analyzed by flowcytometry, and the serum levels of interleukins (IL17A), (IL23) were determined by ELISA.Results: Active RA patients (groups II and III) revealed an obvious increase in peripheral TH17 frequencies, and levels of TH17-related cytokines, and a significant decrease in Treg (CD4+CD25+Foxp3+) frequencies in group III, when compared to healthy controls. TH17/Treg ratios were positively correlated with serum concentrations of IL17A and IL23 cytokines. Frequencies and levels showed statistical significant correlation with DAS scoring.Conclusions: Our study indicated that TH17/Treg balance was disturbed in peripheral blood of RA patients, leading to an increase of proinflammatory cytokines, correlating with DAS, and suggesting an important role in the development of RA.