| Objective: Type 1 diabetes mellitus(T1DM)is an autoimmune disease characterized by T-cell-mediated destruction of pancreatic ? cells.It was 5%-10% in diabetes,half of it for adolescents,who depended on exogenous insulin therapy.On the basis of the genetic susceptibility of islet beta cells for T1DM,the induced effects of environment such as virus infection,milk feeding and stress,resulting in inflammation and destruction of islet beta cells.After the islet beta cells were destroyed,the in itself of antigens in the islet beta cells are released to produce the islet autoantibodies.The islet cell autoantibodies(ICA)has been first reported as a autoantibodies in patients with T1DM in 2007.Since then,the relationship of islet autoantibodies and T1DM had attracted widespread attention.Zinc transporter 8 autoantibody(ZnT8A)is described as a novel target autoantibody a powerful diagnostic and classification marker in patients with T1DM.Latent autoimmune diabetes in adults(LADA)belonged to T1DM subtypes mediated by autoimmune,early presentation at diagnosis similar to patients with type 2 diabetes,without insulin treatment for the first 6 months after diagnosis,the disease process eventually leaded to total dependence on exogenous insulin.Prevalence of the newly diagnosed patient with T2DM over the age of 18 shows about 6.1% in LADA China multicenter collaborative study,but decay rate is 3 times of T2DM about the function of islets of pancreas,Spontaneous diabetic ketoacidosis occurs in the six months to a year after the onset.It was very important for LADA patients to accurate diagnosis and timely insulin therapy.ZnT8A was affected by the number and function of islet beta cells in the disease process.Regardless of age,screening for ZnT8A identified 74% first-degree relatives of T1DM patients who developed diabetes within 5 years.So ZnT8A was immunological marker of T1DM should be focused and monitored.It was reported that predictive value of ZnT8A for T1DM patient in China.Therefore it should be screened and monitored for high risk individuals to protect the remnants of islet beta cell function.Once found hyperglycaemia,in time for early treatment.However,the widely used current ZnT8A radio-ligand binding assay(RBA)has proved to be difficult for many laboratories to implement.On August 20,2014,The U.S.Food and Drug Administration approved firstly ZnT8A enzyme-linked immunosorbent assay in T1DM patients,it was important to T1DM patients.In this study ZnT8A were measured using an ELISA.In order to assessed The diagnostic value of ZnT8A in T1DM.Methods: 1 According to the diagnostic criteria of World Health Organization(WHO)about diabetes in 1999.A total of 194 cases patients were randomly collected from endocrine department one in the Third Hospital of Hebei Medical University,including 84 T1DM patients(50 male,34 female,median age 33 years,range 7–73 years,median duration13 years,Minimum 7days,maximum 25 years).In all T1DM patients,GADA were positive at the onset of the disease.110 T2DM patients were collected at diagnosis,prior to any diabetes treatment(69 male,41 female,age 49.32±13.61 years,range19–84 years).102 normal controls was collected from the medical center of the third hospital of Hebei Medical University during the same period(53 male,49 female,median age 38.5 years,range 15–66 years),and had no known chronic diseases such as heart,brain,liver,kidney and other endocrine condition.Two tube 4ml venous blood sample was collected from all individuals after 12 h of fasting.The blood samples were centrifuged for serum isolation.one isolated serum was used for biochemical detection,another tube serum packed in Eppendorf tubes was frozen and stored at-20? for measuring ZnT8A and GADA.2 ZnT8A were measured using an ELISA.3 GADA were measured using a Radioimmunoassay(RIA).4 The measurement of clinical indicators4.1 Height,weight,waist circumference,hip circumference,Systolic blood pressure(SBP),diastolic blood pressure(DBP)4.2 Triglycerides(TG),total cholesterol(TC),low density lipoprotein cholesterol(LDL-C),high density lipoprotein cholesterol(HDL-C)and fasting blood-glucose(FBG)were measured by automatic biochemical analyzer.Hemoglobin A1c(HbA1c)were measured by turbidimetric inhibition immuno assay.5 Statistical analysis: All statistical analyses were performed with the SPSS version 13.0 Statistical Software Package.Results were shown as mean ±SD((?)±s)or as median(interquartile range)or otherwise documented as positive cases,constituent ratio or ratio.Comparisons between groups were made using the t-test for normally distributed data,Mann–Whitney U-test or the non-parametric Kruskall–Wallis H test for for non-normally distributed data.Differences in proportions between groups were tested using the chi-squared test or Fisher's exact test when appropriate.Sensitivity and specicity was determined using receiver operator characteristic(ROC)analysis.p values less than 0.05 were considered signicant.Results:1 The median of ZnT8A concentration was13.71 U/ml in T1DM patients,6.33 U/ml in T2DM patients and 2.02 U/ml in normal controls,there was signicant difference with the ZnT8A concentration among the three groups(?~2=147.640,P<0.01),the concentration of ZnT8A was significantly higher in T1DM patients compared to T2DM patients and to normal controls(Z=-9.710,-9.623,P<0.01),the concentration of ZnT8A was significantly higher in T2DM patients compared to normal controls(Z=-7.279,P<0.01).The prevalence of ZnT8A was 23.8%(20/84),1%(1/110)and 0%(0/102)respectively among the three groups,there was signicant difference with the prevalence of ZnT8A(?~2=49.719,P<0.01),the prevalence of ZnT8A was significantly higher in T1DM patients compared to both T2DM patients and to normal controls(?~2=29.201,23.970,P<0.01),there were no signicant differences between in T2DM patients and normal controls.The median of GADA oncentration was 1.91 U/ml,0.066 U/ml and 0.063U/ml respectively among the three groups,there was signicant difference the oncentration of GADA(?~2=147.570,P<0.01),the concentration of GADA was significantly higher in T1DM patients compared to both patients T2DM and to normal controls(Z=-10.965,-10.421,P<0.01),there were no signicant differences with both T2DM patients and normal controls.In T1DM patients,prevalence of GADA was 58.3%(49/84),but when combined with ZnT8A,the diagnostic prevalence was increased to 67.9%(57/84),the prevalence of autoantibodies increased 9.6%.2 The median of ZnT8A concentration was 13.40 U/ml in classical T1DM patients(age<18 years)and was 13.71 U/ml in LADA patients(age?18 years),there was no signicant difference with the ZnT8A concentration between the two groups.The prevalence of ZnT8A was 40%(8/20)and18.8%(12/64)between the two groups,there was no signicant difference in the prevalence of ZnT8A.The concentration of GADA was 1.20 U/ml and 3.14 U/ml respectively between the two groups,the concentration of GADA was significantly higher in patient with LADA compared to classical T1DM patients(Z=-2.107,P<0.05).The prevalence of GADA was 50%(10/20)and 60.9%(39/64)respectively between the two groups,there was no signicant difference in the prevalence of GADA.The prevalence of GADA was 50%(10/20)in classical T1DM patients,but when combined with ZnT8A,the prevalence of autoantibodies was increased to 65%(13/20),the prevalence of autoantibodies increased 15%.The prevalence of GADA was 60.9%(39/64)in LADA patients,but when combined with ZnT8A,the prevalence of autoantibodies was increased to 68.7%(44/64),the prevalence of autoantibodies increased 7.8%.3 T1DM group was divided into three subgroups according to the onset years(onset years<18 years,18 years?onset years<30 years and onset years?30 years).The median of ZnT8A concentration was 13.40 U/ml,14.74 U/ml and 13.59 U/ml respectively among the three subgroups,there was signicant difference with ZnT8A concentration(?~2=6.901,P<0.05),ZnT8A concentration was significantly higher at the 18 years?onset years<30 years compared to at the onset years?30 years(Z=-2.263,P<0.01),there was no signicant difference with ZnT8A concentration at the onset years<18 years of the patients compared to at the 18 years?onset years<30 years and at the onset years?30 years.The prevalence of ZnT8A was 40%(8/20),50%(10/20)and 4.5%(2/44)respectively among the three subgroups,there was signicant difference in the prevalence of ZnT8A(?~2=19.454,P<0.01).The prevalence of ZnT8A was significantly higher at onset years<18 years and at the 18 years?onset years < 30 years compared to at the onset years?30 years(?~2=10.559,15.784,P<0.01),there was no signicant difference at the onset years<18 years of the patients compared to at the 18 years?onset years<30 years.The median of GADA concentration was1.2 U/ml,0.53 U/ml and 6.9 U/ml respectively among the three subgroups,there was signicant difference with GADA concentration(?~2=16.911,P<0.01),GADA concentration was significantly higher at the onset years?30 years compared to at the 18 years?onset years<30 years and at the onset years?30 years(Z=-3.217,-3.391,P<0.01),there was no signicant difference at the onset years<18 years of the patient compared to the 18 years?onset years<30 years.The prevalence of GADA was 50%(10/20),40%(8/20)and 71.5%(31/44)respectively among the three subgroups,there was no signicant difference with the prevalence of GADA.4 T1DM group was divided into three subgroups according to the duration(duration<1 year,1 year?duration<5 year,duration?5 years).The median of ZnT8A concentration was 13.54 U/ml,14.04 U/ml and 13.42 U/ml respectively among the three subgroups,there was no signicant difference with ZnT8A concentration.The prevalence of ZnT8A was 33.3%(6/18),21.4%(3/14)and 21.2%(11/52)respectively among the three subgroups,there was no signicant difference with the prevalence of Zn T8 A.The median of GADA concentration was 2.15 U/ml,0.85 U/ml and 2.13 U/ml respectively among the three subgroups,there was nosignicant difference the concentration of GADA.the prevalence of GADA was 55.6%(10/18),50%(7/14)and 61.5%(32/52)respectively among the three subgroups,there was no signicant difference the prevalence of GADA.5 T1DM group was divided into three subgroups according to the BMI(BMI<24kg/m~2,24 kg/m~2?BMI<28 kg/m~2 and BMI?28 kg/m~2).The median of ZnT8A concentration was 13.78 U/ml,13.44 U/ml and 14.27 U/ml respectively among the three subgroups,there was no signicant difference with the ZnT8A concentration.the prevalence of ZnT8A was 25.8%(17/65),23.1%(3/13)and 0%(0/6)respectively among the three groups,there was no signicant difference with the prevalence of ZnT8A.The median of GADA concentration was 2.35 U/ml,0.69 U/ml and 0.09 U/ml respectively among the three subgroups,there was signicant difference with GADA concentration(?~2=8.978,P<0.05),GADA concentration was significantly higher in patient for BMI<24 kg/m~2 and for 24 kg/m~2?BMI<28 kg/m~2 compared to for BMI?28 kg/m~2(Z=-2.834,-2.923,both P<0.01),there were no signicant differences in patients for 24 kg/m~2?BMI < 28 kg/m~2 compared to BMI<24kg/m~2.The prevalence of GADA was 68.2%(45/66),30.8%(4/13)and 0%(0/5)respectively among the three subgroups,there was signicant difference in the prevalence of GADA(?~2=15.49,P<0.01),the prevalence of GADA was significantly higher in patient for BMI<24 kg/m~2 compared to for BMI?28 kg/m~2(?~2=7.486,P<0.01),there were no signicant differences in patients for 24 kg/m~2?BMI < 28 kg/m~2 compared to BMI<24kg/m~2 and BMI?28 kg/m~2.6 T1DM group was divided into four subgroups(alone GADA positive,alone ZnT8A positive,GADA or ZnT8A positive,GADA and ZnT8A positive).The prevalence of four subgroups of T1DM patient was44.0%(37/84),9.5%(8/84),67.9%(57/84)and 14.3%(12/84)respectively,which was signicant difference among four subgroups(?~2=83.748,P<0.01).the prevalence of GADA or ZnT8A positive group was significantly higher compared to alone GADA positive group,alone ZnT8A positive group,GADA and ZnT8A positive group(?~2=9.661,60.249,49.802,both P<0.001);The prevalence of alone GADA positive group was significantly higher compared to alone ZnT8A positive group,GADA andZnT8A positive group(?~2=25.526,18.007,both P<0.001);there was no signicant difference the prevalence of alone ZnT8A positive group and GADA andZn T8 A positive group?7 ROC analysis of ZnT8A showed 23.8% sensitivity and 99% specicity(cutoff 15 u/mL)and AUC was 0.91(95% CI,0.87-0.95)8 T1DM group was divided into ZnT8A positive and ZnT8A negative two subgroups.The age and the onset age of ZnT8A positive group was significantly higher compared to ZnT8A negative group(Z=3.268,3.496,both P<0.01).The HbA1 C and the FBG of ZnT8A positive group was significantly higher compared to ZnT8A negative group(t=2.670,Z=-2.621,P<0.01,P<0.05).ZnT8A positive was more prone to ketosis compared to ZnT8A negative group(?~2=6.159,P<0.05).There were no signicant differences between two subgroups at T1DM gender,family history,duration,WHR,BMI,SBP,DBP,insulin dosage,TC,TG,LDL-C,HDL-C.Conclusions:1 The specicity was high of ZnT8A ELISA,which was a convenient and simple technology method and can be used as a screening and classification criteria of T1DM.2 ZnT8A was of great value in the differential diagnosis of young onset diabetes.3 The prevalence of diagnosis was increased by combined detection of GADA and ZnT8A. |
PDF Full Text Request