INTERLEUKIN-1 RECEPTOR ANTAGONIST GENE POLYMORPHISM ASSOCIATION WITH LICHEN-SCLEROSUS

Cytokines play key roles in immune responses, inflammation and fibrosi s. The balance between levels of cytokines, their receptors and specif ic inhibitors controls inflammatory reactions in tissues. The pathogen esis of lichen sclerosus is unknown but probably involves cytokine med iators such as interleukin 1 (IL-1) and interleukin 1 receptor antagon ist (IL-1ra). The IL-1ra is a competitive inhibitor of IL-1 alpha and IL-1 beta, and therefore is a powerful endogenous anti-inflammatory mo lecule. The gene encoding IL-1ra (designated IL-1RN) has a variable nu mber tandem repeat polymorphism in intron 2. There are five alleles of the gene corresponding to 2, 3, 4, 5 and 6 repeats of an 86-bp sequen ce. We have determined allele frequencies in a control population and a group of 78 patients with lichen sclerosus. The frequency of one of the alleles is related to increasing disease severity. Thus, IL-1RN ma y be a candidate gene or severity factor for lichen sclerosus or may p ossibly be a linked marker to another, as yet undefined, gene.