Study On The Relationship Between Polymorphism Of Toll Like Receptor 4 Gene, CD14 Gene And Atopic Diseases In Chinese Han Children

Objective To investigate the distribution characteristics of the single nucleotide polymorphisms (SNPs) of the human Toll-like receptor 4 ( TLR4 ) gene and CD14 gene in Chinese Han children in Wenzhou, and their relation to atopic diseases. Methods 113 cases were recruited in atopic disease group with the criteria as follows: 2-12 years old, clinically diagnosed as asthma or allergic rhinitis or atopic dermatitis, elevation of serum total IgE levels and serum specific IgE. 67 healthy children.were enrolled in control group. The related region of TLR4 gene contained Asp299Gly and Thr399Ile polymorphisms and CD 14 gene were sequenced to identify and characterize the SNPs, and plasma TIgE and SIgE were detected by immunoassay system and uniCAP system respectively. The frequency of genotypes and alleles between two groups, as well as the levels of IgE in different genotypes, were compared. Results1.In atopic disease group, the rates of positive reaction to both Phadiatop and fx5E , mere positive reaction to Phadiatop , mere positive reaction to fx5E , negative reaction to Phadiatop and fx5E were 8.9%, 59.3%,24.8%,and6.2%,respectively. The mean age of atopic children with mere positive reaction to Phadiatop was significantly older than that of atopic children with mere positive reaction to fx5E((7.69±2.28) year vs (3.75±1.89) year);2.We did not find Asp299Gly and Thr399Ile polymorphisms in the toll-like receptor 4 gene in both groups;3.CD14/-159 SNP was present in Han population of Wenzhou. The frequency of eachgenotype was 57.0%(TT) 28.0%(TC) 15.0%(CC) in normal children., and46.9%(TT) 35.4% (TC) 17.7% (CC) in atopic children. No significant difference wasfound in the distribution of CD 14/-159 polymorphism between atopic children andhealthy control (x~2 = 1.918 , P>0.05) according to Hardy-Weinberg principlestatistics.4.There was no significant difference in the distribution of CD14/-159 polymorphismamong different ages of atopic children . In healthy control, the frequency of TCgenotype in 2-3 years old group was higher than other groups, (%?—12.020, P<0.05).There were no difference in frequency of each genotype between male andfemale children.5. No significant difference was found in the total plasma IgE levels among groups ofTT genotypes [ (2. 52 ±0. 46) IU/ml ],TC genotypes [ (2. 40 ±0. 46) IU/ml ]and CCgenotype[ (2.50 + 0.46) IU/ml] (F=0.807, P>0. 05) .Conclusion1 .There are age distribution characteristics of allergen-specific serum IgE antibodiesin clinically-diagnosed atopic children. Infants mainly present food allergensensitization , and the prevalence of inhalant allergen sensitization increased in olderchildren.2.Asp299Gly and Thr399Ile polymorphisms in the toll-like receptor 4 gene are notcommon in Han children in Wenzhou.3.CD14/-159 SNP is present in Han children in Wenzhou, and other SNP in CD 14gene was not found. TT genotype is the primary genotype in CD14/-159 SNP in Hanchildren in Wenzhou.4.No relationship between CD 14/-159 SNP and atopic disease or serum total IgElevel was found.