Regulatory effect of nicotine on the differentiation of Th1, Th2 and Th17 lymphocyte subsets in patients with rheumatoid arthritis

Peripheral blood mononuclear cells (PBMCs) and CD4+T cells were separated from patients with RA. PBMCs were stimulated with anti-CD3/anti-CD28 in the absence or presence of nicotine. CD4+T cells were cultured in the Th cell differentiation condition in the absence of nicotine or nicotine and alpha- bungarotoxin (αBgt) (the antagonist of nicotine) combined. Levels of T cell cytokines were detected with ELISA and flow cytometry. The expression of specific transcription factors (retinoic orphan re- ceptor c (RORc), T-box transcription factor (T-bet), and GATA Binding Protein 3 (GATA-3)) and signaling molecules (P-ERK1/2 and T-ERK1/2) were determined by Western blot. The results showed nicotine reduced IL-17A and increased IL-4 produced by stimulated PBMCs. During Th17 differentiation conditions, nicotine reduced the levels of IL-17A and RORc, induced the phosphorylation of ERK1/2. Meanwhile, nicotine increased the levels of IL-4 and GATA3 during Th2 differentiation. α-Bgt blocked the effects of nicotine on Th2 and Th17 differentiation. However, nicotine had no effect on the expression of IFN-γ and T-bet in CD4+T cells during Th1differentiation. These results demonstrate that nicotine suppresses Th17 differentiation, promotes Th2 differentiation and improves Th1/Th2 imbalance in RA patients, providing a new justification for its application in the treatment of rheumatoid arthritis.