Polymorphisms of TLR7 and TLR8 associated with risk of asthma and asthma-related phenotypes in a southeastern Chinese Han population

Objective To evaluate the effects of polymorphisms in TLR7 and TLR8(as potential candidate genes) on asthma risk and asthma-related phenotypes. Methods We consecutively recruited 318 unrelated adult asthmatic patients and 352 healthy volunteers from the same area of southeast China. Genotyping of each selected SNP was performed using multiplex PCR in conjunction with tagged array single base extension technology. We conducted case-control and case-only association studies between the selected SNPs in TLR7 and TLR8 and asthma or asthma-related phenotypes. Results The T allele of rs5935436 SNP in TLR7 was protective from developing asthma in males (adjusted ORs = 0.126, 95% CIs = 0.016-0.995). The CT/TT genotype of rs5935436 was less frequent in female asthmatics with allergic rhinitis (adjusted ORs = 0.18, 95% CIs = 0.04-0.90). The homozygote AA of rs3761623 and GG of rs3764880 were positively associated with lower FEV1% and asthma severity in female asthmatics. These results were confirmed by haplotype analysis. Conclusion TLR7 and TLR8 polymorphisms may play an important role in the pathogenesis of asthma that is gender-dependent. This could be clinically useful, both for identifying patients at risk of asthma and for preventing its occurrence.