No abstract

Cytokines play key roles in immune responses, inflammation and fibrosis. The balance between levels of cytokines, their receptors and specific inhibitors controls inflammatory reactions in tissues. The pathogenesis of lichen sclerosus is unknown but probably involves cytokine mediators such as interleukin 1 (IL-1) and interleukin 1 receptor antagonist (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 molecule. The gene encoding IL-1ra (designated IL-1RN) has a variable number 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 sequence. 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 may be a candidate gene or severity factor for lichen sclerosus or may possibly be a linked marker to another, as yet undefined, gene.

A variable number of tandem repeats (VNTR) polymorphism has been described in intron 2 of the interleukin-1 receptor antagonist gene. Allele 2 of this polymorphism is associated with many chronic inflammatory diseases. Using direct sequencing of polymerase chain reaction products from individuals of known genotype for the VNTR, we have identified four single base change polymorphisms in exons 1ic and 2 and one upstream of exon 1ic, all of which are probably in linkage disequilibrium with the intron 2 VNTR. The exonic polymorphisms do not alter the encoded amino acid sequence. Using the exon 2 polymorphism as a marker for the intron 2 disease-associated allele, we have been able to analyse allele-specific mRNA in heterozygotic keratinocyte cell lines. The disease-associated allele shows no difference from other alleles in this cell type with respect to mRNA accumulation.

No abstract

A variable number of tandem repeats (VNTR) polymorphism has been described in intron 2 of the interleukin-1 receptor antagonist gene. Allele 2 of this polymorphism is associated with many chronic inflammatory diseases. Using direct sequencing of polymerase chain reaction products from individuals of known genotype for the VNTR, we have identified four single base change polymorphisms in exons 1ic and 2 and one upstream of exon 1ic, all of which are probably in linkage disequilibrium with the intron 2 VNTR. The exonic polymorphisms do not alter the encoded amino acid sequence. Using the exon 2 polymorphism as a marker for the intron 2 disease-associated allele, we have been able to analyse allele-specific mRNA in heterozygotic keratinocyte cell lines. The disease-associated allele shows no difference from other alleles in this cell type with respect to mRNA accumulation.