Genetic Polymorphisms Of Toll-like Receptor 3 In Neonates With Enterovirus Infections

Backgrounds:Enteroviruses are known to occur in high incidence from august to October,and infants are susceptible.Clinical manifestation of enterovirus infections in neonates varies from mild to severe and is diverse.Innate immune response can identify bacteria,viruses and fungi and other pathogenic microorganisms,and rapid response to pathogenic microorganisms;and it is the body’s first line of defense against the invasion of various pathogenic microorganisms.Toll like receptor(TLR)is the main pattern recognition receptor,and it is closely related to many kinds of bacterial and viral infectious diseases in the innate immune response to identify the conserved structure of various pathogenic microorganisms.TLR3 is mainly responsible for the identification of viral double stranded RNA and polyinosinic polycytidylic acid,to trigger an inflammatory response.Recent studies have found that TLR3 plays an important role in the antiviral immune response,but its relationship with enterovirus infections is unclear.In this study,we detected the gene polymorphisms of TLR3 rs3775296,rs3775292,rs3775291,rs3775290,rs13126816,rs5743312 to explore the relationship between genetic polymorphisms of TLR3 and susceptibility of enterovirus infections in neonates.Objectives:To investigate the genetic polymorphisms of TLR3 gene and its relationship with enterovirus infections in neonates,and to explore the genetic susceptibility of enterovirus and the changes of cytokine levels.Methods:Between May 2013 and September 2014,47 infants with enterovirus infections(case group)and 47 infants with non infectious diseases(control group)were enrolled from admissions to the neonatal ward of the Children’s Hospital,Zhejiang University School of Medicine.Blood samples were collected during hospitalization,and the genomic DNA was extracted.we detected the gene polymorphisms of TLR3 rs3775296,rs3775292,rs3775291,rs3775290,rs13126816,rs5743312 of the case group and the control group by Polymerase chain reaction(PCR);and conducted the sequence analysis by direct PCR product sequencing methods;and calculated the genotype frequency and allele frequency.At the same time,the change of cytokine levels(IL-2,IL-4,IL-6,IL-10,TNF,IFN-r)in the two groups were detected by double antibody sandwich ELISA method,and the statistical analysis was carried out.Results:There were C and G alleles in TLR3 rs3775292.The distribution frequency was 30%and 70%respectively in the abnormal ECG group,and 8%and 92%respectively in the normal ECG group.Compared with the abnormal and normal ECG group,the C allele was related to abnormal ECG risk of enterovirus infections in neonates(P<0.05).In the same way,there was no statistical significance in the distribution of the genotype frequencies of TLR3 rs3775292between the abnormal and normal ECG group(P>0.05).There was no statistical significance in the distribution of the genotype and allele frequencies of TLR3 rs3775290,rs3775296,rs3775291,rs13126816,rs5743312 between the abnormal and normal ECG group(P>0.05).There was no statistical significance in the distribution of the genotype and allele frequencies of TLR3 rs3775296,rs3775292,rs3775291,rs3775290,rs13126816,rs5743312 between the case group and control group、the Meningitis group and nonmeningitis group、the fever more than 3 days groups and less than 3 days groups、the thrombocytopenia group and platelet normal(P>0.05).There was statistical significance in the levels of IL-6,IL-10 between the case group and control group(P<0.05).The levels of IL-2,IL-4 was essentially flat between the case group and control group,the levels of TNF,IFN-r increased in the case group,however,there was no statistical significance compared with the control group.Conclusions:The gene polymorphism of TLR3 rs3775296,rs3775292,rs3775291,rs3775290,rs13126816,rs5743312 had no significant association with enterovirus infections in neonates,but also with meningitis of enterovirus infections in neonates、fever duration and thrombocytopenia.The C allele of rs3775292 may be associated with the abnormal ECG risk of enterovirus infections in neonates.IL-6 and IL-10 were frequently increased in enterovirus infections of neonates;IL-2,IL-4,TNF,IFN-r levels had no significant association with enterovirus infections in neonates.