Toll-like receptor 2 (TLR2) gene polymorphisms are not associated with sarcoidosis in the Japanese population

PURPOSE Sarcoidosis is a systemic inflammatory disease characterized by the formation of non-caseating granulomas, with varied clinical manifestations. The common etiology of sarcoidosis is uncertain, but it is thought to be triggered by an exogenous antigenic stimulus, such as some bacterial proteins. Toll-like receptors (TLRs) recognize microbial components and elicit innate as well as adaptive immune responses. It has been reported that polymorphisms in TLR2 might be important in a small group of Caucasian sarcoidosis patients. The present study aimed to establish whether these findings are relevant to the Japanese population. METHODS We genotyped 5 single-nucleotide polymorphisms (SNPs) in TLR2 and assessed the allelic diversity between 257 Japanese sarcoidosis patients and 193 Japanese healthy controls. RESULTS No significant differences in the frequency of TLR2 alleles and haplotypes in the sarcoidosis cases were found in comparison with the controls. However, marginal associations were observed for TLR2 at rs3804099 and rs3804100 in sarcoidosis patients with cutaneous manifestations. CONCLUSIONS Our results suggest that TLR2 polymorphisms are not significantly related to the pathogenesis of sarcoidosis in the Japanese population.