Common polymorphisms in the interleukin-22 gene are not associated with chronic plaque psoriasis.

ABSTRACT

BACKGROUND: Psoriasis is a chronic inflammatory skin disease. Among other cytokines, interleukin 22 (IL-22) has been implicated in the pathogenesis of chronic plaque psoriasis. The purpose of this study was to investigate a hypothesized association between common IL-22 gene polymorphisms and chronic plaque psoriasis. METHODS: Genotypes of 10 common polymorphisms of the IL-22 gene were determined by fluorogenic 5' exonuclease assays (TaqMan) in 475 patients with chronic plaque psoriasis and 252 controls. RESULTS: Two blocks of high linkage disequilibrium, formed by eight polymorphisms upstream of exon 5 (rs2227485, rs2227491, rs2046068, rs1179251, rs1012356, rs2227501, rs2227503, rs976748) and two polymorphisms in the 3' near gene region (rs1182844, rs1179246), were observed within the IL-22 gene. Neither single polymorphisms nor haplotypes were significantly associated with the presence or clinical features of chronic plaque psoriasis (P > 0.05). CONCLUSIONS: Our data suggest that the investigated IL-22 gene polymorphisms are unlikely major risk factors for chronic plaque psoriasis.