Association analysis of IL1A and IL1B variants in alopecia areata

Alopecia areata is an inflammatory hair loss disease with a major genetic c omponent. The disease is characterized by focal inflammatory lesions with p erifollicular T-cell infiltrates, reflecting the role of local cytokine pro duction in the development of patchy hair loss. IL-1 alpha and IL-1 beta ar e important inhibitors of hair growth in vitro. Their effect is opposed by the interleukin-1 receptor antagonist, IL-1ra. Genes of the IL-1 cluster ar e candidate genes in the pathogenesis of alopecia areata. To investigate th e role of the IL-1 system in alopecia areata we examined three biallelic po lymorphisms within the IL-1 gene cluster (IL1A+4845, IL1B+3954 and IL1B-511 ) in 165 patients and a large number of matched controls (n = 1150). There was no significant association of IL1B-511 or IL1B+3954 genotypes with the overall dataset, or with disease severity or age at onset, in contrast with a previous report. The results suggested the possibility of an association with IL1A+4845 in the overall dataset [OR 1.39 (95% Cl 1.00, 1.93)] althou gh this was not statistically significant. This was due mainly to the contr ibution from mild cases of alopecia areata [OR 1.48 (0.96, 2.29)], suggesti ng that IL-1 alpha may have a particular role in the pathogenesis of this s ubgroup.