Association Between the Interleukin 6 Genotype at Position –174 and Atopic Dermatitis

Abstract: Atopic dermatitis (AD) is a chronic skin disorder of unknown origin that usually manifests for the fi rst time in early infancy. Different types of genetic predisposition and environmental factors seem to be associated with the disease. Methods: This study was performed to evaluate the frequency of alleles, genotypes, and haplotypes of interleukin (IL) 6 single-nucleotide polymorphisms (SNPs) at positions –174 and nt565 in 89 Iranian children with AD and 139 healthy controls. Results: The G allele was signifi cantly more frequent at position –174 in IL6 in atopic patients than in the healthy controls (P<.001; OR, 2.82). Genotype GG was found at the same position in 71% of the patients; this frequency was signifi cantly higher than the frequency of 30% recorded in the controls (P<.001; OR, 5.60). The GG haplotype of IL6 (–174, nt565) was signifi cantly more frequent in the atopic patients than in the healthy controls (P<.001; OR, 2.99). Conclusions: A signifi cant increase in the frequency of the G allele and GG genotype at position –174 of IL6 was found in patients with AD, thus suggesting that production of this cytokine is greater in atopic patients. Key words: Atopic dermatitis. Cytokine. Single gene polymorphisms. Interleukin 6.