Influence of and Gene Polymorphisms on the Spondyloarthritis Immunopathogenesis, Regardless of HLA-B27, in a Brazilian Population.

Background And Objectives: Spondyloarthritis (SpA) represents a heterogeneous group of immune-mediated inflammatory diseases that have overlapping clinical features, genetic predisposition, and pathogenic mechanisms. Hence, we investigated, through a case-control study, whether single-nucleotide polymorphisms of and genes are associated with SpA, ankylosing spondylitis (AS), and psoriatic arthritis (PsA) in a mixed Brazilian population.

Methods: Genotyping of -308 (rs1800629), -238 (rs361525), (rs2275913), (rs763780), and polymorphisms was performed in 243 patients with SpA and 210 controls from Southern Brazil using SSOP-Luminex (One Lambda) and PCR-SSP assays.

Results: Significant associations were confirmed between the HLA-B27 marker and SpA, AS, and PsA diseases. While -308 (rs1800629) AA/GA, (rs2275913) AA/GA, and (rs763780) CC/TC genotype frequencies were associated, in the dominance inheritance model, with SpA and AS, regardless of gender, the presence of , -238 (rs361525) GA/AA, (rs2275913) AA/GA, and (rs763780) genotypes was associated with PsA.

Conclusion: In this Brazilian population, and gene polymorphisms responsible for the expression of important inflammatory cytokines were associated with overall SpA, and, specifically, with AS and PsA, regardless of gender and . However, future larger studies with different ethnicities may be necessary to confirm these genetic associations.