IL6 -174G>C polymorphism is associated with an increased risk of psoriasis but not response to treatment.

Interleukin-6 (IL-6) is implicated in the pathogenesis of psoriasis as well as in its treatment efficacy. The aim of this study of 406 patients with psoriasis and 203 healthy controls was to evaluate the association between the IL6 -174G>C (rs1800795) polymorphism and psoriasis susceptibility, as well as treatment efficacy. The frequency of genotype GG (33.7% vs. 20.7%; P = 0.00022; OR = 0.51, 95% confidence interval 0.34-0.76) and of allele G (56.2% vs. 46.8%; P = 0.0023) was significantly higher in the psoriasis group compared with controls. No polymorphism variants were associated with better response to topical or combined topical/narrow-band ultraviolet B (NB-UVB) treatment. We conclude that the IL6 -174G>C polymorphism can be a marker of susceptibility to psoriasis, with an almost twofold increased risk of the disease in individuals carrying the GG genotype; however, it was not associated with treatment response to topical and/or NB-UVB therapy.