To characterize the inflammatory environment contribution to the RA pathogenesis, we estimated the concentrations of different, Th17 or Treg-related cytokines (IL-17, IL-21, IL-22, IL-6, IL-10, IL-35, IL-2, IL-23, TGF-β, IFN-γ) in serum samples. The gene discussed is IL21; the disease is rheumatoid arthritis.