Study On The Genetic Association Of HMGB1 Gene Polymorphism And Susceptibility To Henoch-Schonlein Purpura In Children Of Southwest Shandong

Background and Objective: Henoch-Sch?nlein purpura(HSP)is one of the most common vessel diseases in children,defined as selflimited capillary and small vasculitis,characterized by skin purpura,abdominal pain,arthritis,and even renal mesangiumm,wihch is the most serious complications related with the progression and prognosis.The etiology of HSP is not fully identified,but recent studies focused on genetic factors,infections,drugs,food,ect.With the development of genomics,many studies are focused on the genetic factors.Its incidence rises in recent years,affecting health and quality of life of the patients,so more studies are necessary to reveal the etiology and pathogenesis of HSP.High mobility group box-1(HMGB1)protein involves in the pathogenesis of various autoimmune and inflammatory diseases,involved in the pathogenesis of various autoimmune and inflammatory diseases.HMGB1 gene polymorphisms have been found to be associated with autoimmune and inflammatory diseases,but there were no reports on HSP.The purpose of our study is to evaluate the association between SNPs of HMGB1 gene and the risk of HSP.In addition to identify the expression of HMGB1 in the peripheral blood,and to investigate the clinical significance of HMGB1 in children with HSP.Our study will provide novel and methods for clinical diagnosis,treatment and as well as prevention HSP in children.Materials and methods:1,The selection of peripheral blood samples.The case-control study involved 160 children with HSP and 96 healthy controls between March 2015 and June 2016 at Shandong Ji-ning No.1 People’s Hospital,department of dermatology,pediatrics,nephrology and hematology.2,Screen the tag SNPs.The sequencing scope of HMGB1 gene was from transcription promoter to terminator witnin 3-10 Kb,through the linkage disequilibrium structure diagrams,and previous literatures,our study finally selected three tag SNPs: rs2249825,rs1045411,rs1412125.3,Determine the scope of the sequence,then design primers.Sequencing scope includes four exons and three tag SNPs in the introns,a total of 6 for primers were designed.The genotypes were obtained according to outcomes which sequenced by 3730 XL DNA analyzer.4,Statistical analysis.The genotype frequency and allele frequency of SNPs were tested by H-W balance and statistical analysis,and to screen SNPs associated with HSP/HSPN.5,Select plasma samples of two groups.The exper group contained 60 cases selected randomly from 160 cases of children with HSP,meainwhile,59 cases were selected as control group.6,The determination of plasma HMGB1.The plasma level of HMGB1、IL-6 and TNF-a were detected by enzyme-linked immunosorbent assay(ELISA)detection.7,Statistical analysis.To analysis the difference of HMGB1 in two groups by T test,and the pearson correlation between HMGB1 and the two factors.Results: The CC genotypic frequencies of the rs3742305 was significantly lower in the HSP group than the healthy controls(P=0.014<0.05),and no significant difference was found of C allelic between the two group.The CC genotypic frequencies and C allelic were no signficant differences in the HSPN group and nephritis-free patients.In the other three tag SNPs,no significant differences in allele or genotype frequencies were observed between HSP patients and controls.The levels of HMGB1 in the peripheral blood of the HSP group in the acute phase were significantly higher than in the control group(P=0.002<0.05).The expression of HMGB1 was positively correlated with the expression of IL-6 and TNF-α in HSP children.Conclusion: Our observations suggested the CC genotypicrs in rs3742305 of HMGB1 gene were associated with HSP in Chinese children,and its polymorphism may be a protective factor of HSP.but the polymorphism of rs3742305 was not associated with HSPN,meanwhile,our findings did not support the tag SNP(rs2249825,rs1045411,rs1412125)had an effect on the susceptibility to HSP/HSPN children.The results of ELISA suggested HMGB1 was related to the inflammatory response in children with HSP,HMGB1 may be involved in the development of HSP.