Genetic Polymorphisms Of Toll-like Receptor 3 In Infant With Cytomegalovirus Infection

Research Background:Human cytomegalovirus(HCMV)is a double-stranded DNA virus belonging to the herpes subfamily of herpesvirus group B.It is asymptomatic in most normal immune individuals,but is infected in immunosuppressed individuals,fetuses and infants.Then there can be obvious symptoms.The human body’s natural immune system is the first line of defense against pathogenic microbial infections.It plays an important role in the body’s immune response against external pathogen invasion,and Toll-like receptors(TLRs)act as pattern recognition receptors to recognize Pathogen associated molecular patterns(PAMPs),it play an important role in the immune response.Studies have shown that TLR3(Toll-like receptor 3,TLR3)can specifically recognize viral dsRNA and ultimately bind to DNA fragments,initiate transcription and translation.The body secretes inflammatory factors and cytokines,causing an anti-viral immune response.Some scholars have pointed out that TLR3 plays an important role in the antiviral immune response,and the molecular mechanism of TLR3 and cytomegalovirus infection has not been elucidated.This study was to investigate the relationship between TLR3 gene polymorphism and susceptibility to infant cytomegalovirus infection by detecting TLR3 gene polymorphism(containing rs13126816,rs5743312,rs3775296,rs3775294,rs3775292,rs3775291 locus).Purpose:To investigate the relationship between infant cytomegalovirus infection and polymorphisms of six gene loci(rs13126816,rs5743312,rs3775296,rs3775292,rs3775291,rs3775290)of TLR3 gene,and to study the genetic susceptibility of cytomegalovirus infection.Method:The subjects were hospitalized infants in the neonatal ward of the Children’s Hospital of Zhejiang University School of Medicine from September 2013 to June 2016.Among them,there were 102 infants with cytomegalovirus infection and 106 cases with non-cytomegalovirus infection.Collecting their blood samples,extracting genomic DNA from blood samples,and detecting the genetic polymorphisms of 6 gene loci of TLR3 genes(rs13126816,rs5743312,rs3775296,rs3775292,rs3775291.rs3775290)in each group by polymerase chain reaction(PCR),and SNPscanTM Techniques were used to classify the TLR3 gene points,compare their genotypes and allele frequencies,and perform statistical analysis.Result:Among them,TLR3 gene rs13126816 has three genotypes of AA,GG and AG,and there are two alleles of A and G.The results show that the three genotypes AA,GG and AG and the A and G alleles are giant.There was no significant difference in the distribution between the virus-negative group and the positive group(P>0.05).Further analysis of the genotype and allele frequencies of the TLR3 gene rs5743312,rs3775296,rs3775292,rs3775291,rs3775290 locus revealed that there was no significant difference in genotype and allele frequency between the cytomegalovirus negative group and the positive group(P>0.05).Cytomegalovirus infection can cause abnormal liver function,thrombocytopenia,hearing loss,etc.,and liver dysfunction group and normal value,thrombocytopenia group and platelet normal group,hearing damage group and hearing normal group were compared.The difference in TLR3 gene polymorphism was also compared between the age of admission of cytomegalovirus infection>21 days and the age of admission ≤21 days,the cytomegalovirus copy number and the low group TLR3 gene polymorphism.There was no significant difference in genotype and allele frequency between the above sites(P>0.05).Conclusion:The polymorphisms of the six SNPs of the TLR3 gene,rs13126816,rs5743312,rs3775296,rs3775292,rs3775291,and rs3775290,were not significantly associated with the onset of cytomegalovirus infection in infants.And also there was no significant association with the severity of cytomegalovirus infection.