Influence of <i>IL10</i> and <i>TGFB1</i> Promoter Polymorphisms on Serum Cytokine Levels in Development and Severity of RA

In our study, we focused on the role of the immunosuppressive cytokines TGF-β1 and IL-10 in RA and, in particular, the influence of the IL10-1082 A/G (rs1800896) and TGFB1-509C/T (rs1800469) promoter polymorphisms on their levels as a prerequisite for RA and disease activity clinical features. We found significantly higher IL-10 and lower TGF-β1 serum levels in women with RA than in controls. Patients who carried the -1082AA and AG genotypes had significantly higher levels of lnIL-10 compared to GG in contrast to healthy women carrying the same genotypes. The heterozygous -1082AG genotype was less frequent in RA cases (45.4%) than in healthy women (56.1%) and could be a protective factor for RA development (over-dominant model, OR = 0.66 95% CI 0.38–1.57). In addition, RA patients carrying the heterozygous -1082AG genotype were less likely to be anti-CCP positive than those carrying the homozygous AA/GG genotypes (37.1% vs. 62.9%; OR = 0.495. 95% CI 0.238–1.029, p = 0.058). There was no association between TGFB1 -509C/T SNP and susceptibility to RA and no relation between systemic TGF-β1 levels and rs1800469 genotypes. In conclusion, the IL10-1082 genotypes affect the serum levels of IL-10 in women with RA in a different way from that in healthy women and appear to play a role in the genetic predisposition and autoantibody production in the Bulgarian population