Polymorphic variation of the DEFB1 gene might contribute to the development of ankylosing spondylitis: a preliminary study.

Background: Ankylosing spondylitis (AS) is an inflammatory disease that affects the spine and can cause peripheral arthritis, enthesitis, and dactylitis, as well as extra-articular manifestations such as uveitis and inflammatory bowel disease. β-Defensins are antimicrobial peptides involved in the activation and regulation of several immune cell types that may influence the inflammatory response in AS. The aim was to analyze the association and interaction of two functional variants of the DEFB1 gene in AS patients, and their role with inflammatory markers.

Methods And Results: The rs11362 and rs1800972 variants were genotyped using TaqMan probes in Mexican AS patients and controls. C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR) were quantified. SPSS software was used for statistical analysis and multifactor dimensionality reduction (MDR) for interactions. The AA and GG genotypes were associated with AS risk in the age- and sex-adjusted model (OR = 6.89, P = 0.008 and OR = 3.43, P = 0.046, respectively); furthermore, the A-G haplotype showed a significant association with AS risk (OR = 2.94, P = 0.012). ESR and CRP were elevated in carriers of the AA genotype compared to the GA and GG genotypes of the rs11362 variant (20.89 ± 9.78 vs. 5.63 ± 4.61 and 4.10 ± 2.65 mm/h, P < 0.0001; and 10.92 ± 14.09 vs. 2.14 ± 2.02 and 2.15 ± 2.13 mg/L, P < 0.001, respectively). Using the MDR method, strong interactions of the rs11362 variant with sex were identified in the adjusted and unadjusted models.

Conclusions: These results suggest that the DEFB1 gene may play a key role in AS pathogenesis.