Associations of Toll-like receptor 7 and 8 Polymorphisms with Asthma and Asthma-related Phenotypes in a Chinese Han Population

Toll-like receptor (TLR) 7 and 8 mediate anti-virus immunity and are of particular relevance to asthma. However, very little information about genetic association on TLR7/8 and asthma are available. This study aimed to evaluate the effects of polymorphisms in TLR7 and 8 on asthma risk and asthma-related phenotypes in a Chinese Han population. We enrolled 462 unrelated adult asthmatic patients and 398 healthy volunteers. The genotypes of tagging single nucleotide polymorphisms (SNPs) in TLR7 and 8 genes were determined using multiplex SNaPshot SNP genotyping assay. We used case-control and case-only studies to assess any links with asthma and asthma-related phenotypes. There was no association between the variants in TLR7 and 8 and asthma susceptibility. However, our results revealed that the genetic variants in TLR7 and 8 were associated with asthma-related phenotypes, including eosinophil counts, serum immunoglobulin E levels, lung function, and asthma severity as well. Our study suggests that TLR7 and 8 polymorphisms may play a considerable role in the pathogenesis of asthma. It will help in better understanding the pathogenesis of asthma and development of more effective strategies for asthma prevention, prediction, and therapy.