We analyzed correlations among the proportion of examined T helper subpopulations (Th1, Th17, and Treg) in PB, serum soluble factors (IL-6, IL-2, IFN-γ, TNF, and IL-17), and clinical and/or laboratory features of RA in all studied groups of patients before and after the treatment. This evidence concerns the gene IL17A and rheumatoid arthritis.