Atorvastatin upregulates regulatory T cells and reduces clinical disease activity in patients with rheumatoid arthritis

In this study, we investigated the hypothesis that regulatory T cells (Treg) are involved in the immunomodulatory effects of statins on rheumatoid arthritis (RA) patients. The 12-week study cohort consisted of 55 RA patients and 42 control subjects allocated to either a group treated with atorvastatin (AT) (20 mg/day) or a non-AT group. Treg numbers, suppressive function, serum inflammatory markers, and disease activity were evaluated before and after the therapy. Furthermore, the effects of AT on the frequency and suppressive function of Treg were determined in vitro. Our data revealed that the suppressive function of Treg from RA patients significantly decreased compared with that of control subjects. AT significantly reduced erythrosedimentation, C-reactive protein, and disease activity. Concomitantly, Treg numbers and suppressive functions were significantly improved by AT. Consistent with the in vivo experiments, AT promoted the generation of Treg from primary T cells and enhanced preexisting Treg function in vitro. Moreover, we showed that PI3K-Akt-mTOR and ERK signal pathways were involved in the induction of Treg by AT. In conclusion, AT significantly increased Treg numbers and restored their suppressive function in the RA patients, and this may be relevant in the modulation of uncontrolled inflammation in this disorder.