The Association Between TLR4 Polymorphism And Henoch–sch(?)nlein Purpura In Children

ObjectiveTo investigate the asssociation of single nucleotide polymorphism of Toll like receptor 4(TLR4)gene with Henoeh-Sch(?)nlein purpura(HSP)in children.MethodsA total of 156 children with HSP hospitalized in the Affiliated Hospital of Qingdao University from April 2021 to March 2022 were enrolled as cases group,and 152 healthy children who underwent physical examination during the same period of time were enrolled as control group.The children in the cases group were divided into HSP group and HSPN group according to the presence or absence of renal damage.According to the presence or absence of abdominal pain or arthralgia symptoms,they were divided into a group with abdominal pain,a group without abdominal pain,a group with joint pain,and a group without joint pain.Clinical data of children in each group were collected.Peripheral blood was collected and whole blood DNA was extracted by Flexi Gene DNA Kit.Three single nucleotide polymorphisms(rs2149356,rs11536889,rs7873784)of TLR4 gene were genotyped by improved multiplex ligase detection reaction(i MLDR),and their correlation with HSP were analyzed.Results1.The test results of Hardy-Weinberg balance law showed that the genotype distribution of TLR4 gene rs2149356,rs11536889 and rs7873784 in normal control group was consistent with the law of genetic balance(P>0.05),which indicates that the population has reached genetic balance,that is,good population represation.2.There were no significant differences in genotype frequency and allele frequency of rs2149356,rs11536889,rs7873784 between the HSP group and the normal control group(P>0.05).3.There were statistically significant differences in rs2149356 genotype(TT,GT,GG)frequency and allele(T/G)frequency between HSPN group and NHSPN group(P<0.05).In the dominant model,the sum of T/T and G/T genotype frequencies at rs2149356of NHSPN children was significantly increased compared with GG genotype frequencies(?~2=6.047,OR=0.4136,P<0.05).The T allele was associated with a reduced risk of HSPN(?~2=6.946,OR=0.508,P<0.01).On the contrary,the G allele was an increased risk of kidney damage in children with HSP.4.The results of linkage unbalance and haplotype analysis showed that the D’value between rs2149356 and rs11536889 in HSPN group and NHSPN group was 0.93,and the D’value between rs11536889 and rs7873784 was 1,the D’value between rs2149356 and rs7873784 was 0.84.The frequency of GC haplotype at rs2149356 and rs11536889 in HSPN group was higher than that in NHSPN group,and the comparison between the two groups was statistically significant(P=0.0294,OR=2.1456,95%CI=1.1246-4.0935),suggesting that the GC haplotype(rs2149356,rs11536889)was a risk factor for renal damage in children with HSP.5.The sensitivity and specificity of TLR4 risk allele G(rs2149356)in predicting kidney injury in children with HSP were 91.67%and 20.37%,respectively.The false negative rate was 8.33%and the false positive rate was 79.63%.The sensitivity and specificity of risk haplotype GC(rs2149356,rs11536889)to predict kidney injury in children with HSP were 47.92%and 68.52%,respectively.The false negative rate was52.08%and the false positive rate was 31.48%.6.There were no significant differences in genotype frequency and allele frequency of rs11536889 and rs7873784 between HSPN group and NHSPN group(P>0.05).7.There were no significant differences in genotype frequency and allele frequency of rs2149356,rs11536889,rs7873784 between abdominal pain group and non-abdominal pain group(P>0.05).8.There were no significant differences in genotype frequency and allele frequency of rs2149356,rs11536889,rs7873784 between arthralgia pain group and non-arthralgia pain group(P>0.05).Conclusion1.Single nucleotide polymorphism at rs2149356 of TLR4 gene is associated with the susceptibility to HSPN.With the genetic background of TLR4-rs2149356 allele G and haplotype GC(rs2149356、rs11536889),the risk of renal damage in children with HSP may be increased.Risk allele G and haplotype GC may have potential predictive value for renal damage in children with HSP.2.No correlation was found between single nucleotide polymorphisms at rs11536889,rs7873784 of TLR4 gene and susceptibility or clinical manifestations to children with HSP.