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.