Correlations of IL6R gene polymorphism with pediatric asthma susceptibility

Objective: To characterize the correlations between IL-6R gene polymorphism and pediatric bronchial asthma susceptibility, and to compare the serum levels of upstream IL-6 and downstream total IgE concentrations of IL-6R between children with bronchial asthma and healthy controls. Methods: A total of 260 patients were selected among the Han children with bronchial asthma admitted to the Department of Pediatrics in the Shandong Provincial Third Hospital and assigned to the case group; meanwhile, 300 healthy Han children were assigned to the control group. Blood samples were collected from peripheral veins of the enrolled children, and the DNA was extracted. TaqMan probes and ABI7300 PCR devices were applied to detect the allele and genotype frequencies of IL-6R rs12083537 and rs4845374 SNP loci in children of the two groups. The disparities in the distribution of allele and genotype frequencies between the two groups were compared with the application of the chi-square tests and the Fisher's exact tests. The Hardy Weinberg equilibrium was analyzed by the Stata software, version 11. The serum levels of IL-6 and total IgE concentrations were measured using the ELISA. Results: The genotype distribution of IL-6R rs4845374 and rs12083537 loci of all the children in both groups were in line with the Hardy Weinberg equilibrium. The IL-6R rs12083537 genotype (P=0.027) and allele (P=0.002) frequency distribution in children were markedly different in the two study groups; but the IL-6R rs4845374 genotypes (P=0.129) and allele (P=0.101) were similar; the AA genotype was a risk factor for pediatric bronchial asthma (P=0.019). The serum levels of IL- 6 and total IgE concentrations among children in the case group were substantially higher than those in the control group (Both P<0.05), with considerably elevated serum total IgE concentrations in children with GG, AG and AA genotypes in the case group (All P<0.05). Conclusion: There was a correlation between polymorphism of IL-6R rs12083537 locus and pediatric bronchial asthma, and the AA genotype is one of the risk factors for asthma in childhood.