Research On The Relationship Between Interleukin-6 As Well As-572G/C Polymorphism Of Interleukin-6 Promoter And Type 1 Diabetes Of Children

Objective Type 1 diabetes is a common disease of chinldren,The pathogenesis of type 1 diabetes involve genetically factors,environmental factors and immunological factors.Type 1 diabetes belongs to polygenic disease.IL-6 is considered to play a roal in the pathogenesis of type 1 diabetes,so we detected the level of IL-6 of patients and controls to study the change of IL-6 level in children of type 1 dianbetes,in the same time,we detected the genotype of IL-6-572 of patients and controls by Polymerase Chain Reaction-Restriction Fragment length Polymorphism(PCR-RFLP)to study the relationship between -572G/C polymorphism of IL-6 promoter and type 1 diabetes, we also studied the difference of IL-6 level,the onset year and the C peptide between different genotype of IL-6-572.Methods1 The level of IL-6 of patients and controls was detected by Radioimmunologic method.2 The DNA of patients and controls was extracted by salt fractionation and the purity of DNA was detected by 1.0%agarose gel electrophoresis.3 The promoter of IL-6-572 was amplificated by PCR and the amplification was detected by 2.5%agarose gel electrophoresis.4 The amplification was cut by incision enzyme MbiⅠand the genotype was detected by 3.0%agarose gel electrophoresis to undertake qualitative analysis.5 The C peptide of patients and controls was detected by Radioimmunologic method.6 The representation of genotype of patients and controls was detected accorrding to Hardy-Weinberg equilibrium.7 The data was analyzed by sofeware of spss15.0,The IL-6 level of patients and controls and the IL-6 level of preliminary diagnosed patients and re-examination diagnosed patients were all compared by two indepentent t test.The -572 genotype frequencies of IL-6 promoter of patients and controls were compared by Fisher exact probability test,the IL-6-572 allele frequencies were compared byχ~2 test and the relative risk was expressed by OR and 95%CI.The IL-6-572 disposition of different countries were compared byχ~2 test or Fisher exact probability test.The IL-6 level,the onset year,the C peptide of different genotype were also compared by two indepentent t test.Results1 There was no difference between patients and controls in spite of sex and age.2 The level of IL-6 was not different between patients and controls,and the level of IL-6 was also not different between the preliminary diagnosed patients and re-examined diagnosd patients.3 The amplification of IL-6 -572 was 163bp and there were three genotypes after cuting by incision enzyme,CC genotype was one bright bar(163bp)on the electropherogram,CG genotype was three bright bar(163bp,101bp,62bp)and GG genotype was two bright bar(101bp,62bp)on the electropherogram.4 The genotype and allele frequencies of IL-6-572 were all in Hardy-Weinburg equilibrium,so the patients and controls were representative.5 The IL-6-572 genotype and allele frequencies were not different between the controls and other Chinese people and Japanese,but which were different between the controls and France and American.6 The IL-6-572 genotype and allele frequencies were different between the patients and the controls(P＜0.05),the relative risk of allele of type 1 diabetes indicated G allele was 1.939 times to the G allele,odds ratio is 1.939,95%confidence interval is 1.023～3.678.(OR=1.939,95%CI=1.023～3.678)7 The comparison of the level of IL-6 between GG+GC genotype and CC genotype had no statistical significance.(P＞0.05)8 The comparison of the onset year between GG+GC genotype and CC genotype had statistical significance(P＜0.05),the onset year of child who take along G allele was earlier than the C allele.9 The comparison of C peptide between GG+GC genotype and CC genotype had no statistical significance.(P＞0.05)Conelusion(1)The level of IL-6 is not different between patients and controls,the IL-6 level is also not different between different genotypes of IL-6-572.(2)Different race has different frequency of IL-6-572 genotype and allele,The Asian have resemble frequency of IL-6-572 genotype and allele,and the European and American have resemble frequency.(3)IL-6-572 polymorphism is maybe associated with type 1 diabetes of children and the G allele maybe the predisposing gene of type 1 diabetes of children.(4)The different genotype of IL-6-572 is maybe associated with the onset year,the onset year of child who take along GG+GC genotype is earlier than the CC genotype.(5)The different genotype of IL-6-572 is not associated with C peptide.