Serum Tevel Of Tissue Tarnsglutaminase Anitbody In Patients With Type1Diabetes

Background: Type1diabetes is a chronic metabolic disease causedby islet beta cells selective destruction. T1DM is an autoimmune diseasemediated by autoreactive T lymphocytes. Some autoantibodies can bedetected in the serum of T1DM patients, such as insulinautoantibody(IAA), glutamic acid decarboxylase antibody(GADA),insulinoma associated protein-2antibody(IA-2A) and zinc transporter8antibody(ZnT8A) which was found in recent years. T1DM patients tendto develop other autoimmune diseases，such as coeliac disease(CD).Tissue transglutaminase antibodies (tTGA) can be detected in the sera ofCD patients. Some studies have shown that there is an associationbetween T1DM and CD. tTGAs may can be detected in the sera of T1DMpatients. But association between autoantibodies of T1DM and tTGA isnot well known.Objective: To detect the levels of IA-2A, GADA, ZnT8A and tTGAin sera of T1DM patients by radioligand assay which may parovide auseful way for early screening and prevention of CD in patients withT1DM.Materials and Methods: On the basis of WHO1999diabeticdiagnostic criteria and typing standard，ninety patients with type1diabetes(male41and female49aged3to57years old) were recruitedfrom the Second Hospital of Jilin University from March2012toDecember2012. The durations of T1DM patients are less than12months.A total of107patients with newly diagnosed T2DM (male65and female 42，aged12to77years old) were selected as T2DM group, excludingfrom gestational diabetes and other autoimmune diseases. One-hundredand four healthy volunteers with normal fasting and2h postprandialblood glucose and without family history of diabetes and otherautoimmune diseases were recruited as healthy control group. This studywas approved by the appropriate ethical committees and informedconsent was obtained from all participants. The positive and negativecontrol serum samples were endowed by Barbara Davis Center forChildhood Diabetes IA-2A, ZnT8A, GADA and tTGA autoantibodieswere detected through radioligand assay. Data were analyzed by SPSS21.0statistic software.Results: The positive rates of IA-2A, ZnT8A, GADA and tTGA inthe T1DM group were30.0%（27/90）,30.0%（27/90）,33.3%(30/90) and13.3%(12/90), respectively. The positive rates of IA-2A, ZnT8A, GADAand tTGA in the T2DM group was1.9%（2/107）,2.8%（3/107）and3.7%（4/107）, respectively. The positive rates of IA-2A, ZnT8A, GADA andtTGA in the healthy control group were1%（1/104）. The positive rates ofIA-2A, ZnT8A, GADA and tTGA in the T1DM group were higher thanthose in the T2DM group significantly (P <0.05). The level of tTGA inserum was negatively related to BMI value (R=-0.258, P<0.001) in theT1DM group. The positive rates of IA-2A and ZnT8A in patients youngerthan20years old were higher than those in patients older than20yearsold in the T1DM group (P <0.05). But positive rates of GADA and tTGAdidn’t show significant difference between the two age groups. Thepositive rate of any three autoantibodies in T1DM group was65.6%,higher than that of single antibody detection（p<0.001）.Conclusion: Combined detection of multiple islet autoantibodies can increase the positive rate and contribute to the early diagnosis ofT1DM. T1DM patients tend to develop CD. Screening tTGA in T1DMpatients is necessary and help to diagnose and prevent the development ofCD.