Design and Measurement of Nonislet-Specific Autoantibodies for the Type 1 Diabetes Genetics Consortium Autoantibody Workshop

Interpreting positive celiac serology in children with new-onset type 1 diabetes

OBJECTIVES

The association of celiac disease (CD) in type 1 diabetes mellitus (T1DM) is well-established, yet variation exists in screening practices. This study measures the accuracy of early screening with tissue transglutaminase immunoglobulin A (TTG-IgA) and endomysial antibody (EMA) in newly diagnosed T1DM.

METHODS

This is a retrospective study of children with T1DM between 2013 and 2019 with early CD screening and follow-up. Data elements included anthropometrics, serologies, blood pH, bicarbonate, and Hemoglobin A1c. Celiac serologies were analyzed using chi-square and receiver operating characteristic curves to calculate optimal levels for predicting CD.

RESULTS

A total of 1,292 children met inclusion criteria with 142 having positive celiac serologies; 47 (33.1 %) of whom were subsequently diagnosed with CD - an incidence of 3.6 %. All subjects with positive EMA and TTG-IgA ≥8 times upper limit of normal were diagnosed with CD. Gastrointestinal symptoms, BMI, and thyroid disease were not statistically significant variables in this cohort, although there was a trend toward CD in lower BMI patients and higher TTG IgA in those with markedly elevated HgbA1c.

CONCLUSIONS

Early celiac screening in T1DM is reliable and promotes timely CD diagnosis and treatment. Although transient positive celiac serologies were noted, the degree of TTG-IgA elevation and EMA positivity are strong predictors of coexisting CD. Larger prospective studies using these assays will further define the risk stratification algorithm that is needed for our T1DM community.

The hospitalization profiles of patients with or without diabetes treated for nontraumatic lower extremity amputation in Ribeirão Preto, São Paulo State, Brazil, 2001-2008

The aim of this retrospective study was to assess the hospitalizations of patients with or without diabetes mellitus (DM) who underwent nontraumatic lower extremity amputation (NLEA) with regard to demographic and hospitalization-related variables. It is a high proportion of hospital beds in developing countries, for patients with diabetes mellitus with lower extremity complications. Nontraumatic amputations of lower extremities rates is an important indicator to assess the effectiveness of efforts to reduce chronic complications related to diabetic foot.A total of 2,296 hospital admissions were analyzed with regard to gender, age, length of stay, type of financing, origin, diagnosis, number of hospital admissions and readmissions, and hospitalization outcome from 2001 to 2008 in a municipality of Southeast Brazil. The association between the independent variables and the number of hospitalizations of patients with or without diabetes was assessed using chi-square tests for gender, type of financing, and hospitalization outcome and using the Mann-Whitney U test for age and length of stay. A total of 58% were patients without diabetes, 62.6% were male, 74.5% were treated at a public health care service, and 7.6% died. The mean age was 62.7 years, the mean length of stay was of 9.5 days, and the mean number of readmissions was 2.29 times. The length of stay was higher (P < .001), and the number of men was lower (P = .001) among the patients with diabetes who were hospitalized compared with patients without diabetes.The number of hospitalizations related to NLEA increased among patients with diabetes but reduced among those without diabetes between 2001 and 2008.

Shared Genetic Basis for Type 1 Diabetes, Islet Autoantibodies, and Autoantibodies Associated With Other Immune-Mediated Diseases in Families With Type 1 Diabetes

Type 1 diabetes (T1D) is a polygenic autoimmune disease that is often present with autoantibodies directed against pancreatic islet proteins. Many genetic susceptibility loci are shared with other autoimmune or immune-mediated diseases that also cosegregate in families with T1D. The aim of this study was to investigate whether susceptibility loci identified in genome-wide association studies (GWAS) of T1D were also associated with autoantibody positivity in individuals with diabetes. Fifty single nucleotide polymorphisms (SNPs) were genotyped in 6,556 multiethnic cases collected by the Type 1 Diabetes Genetics Consortium (T1DGC). These were tested for association with three islet autoantibodies-against autoantibodies to GAD (GADA), IA-2 (IA-2A), and zinc transporter 8 (ZnT8A)-and autoantibodies against thyroid peroxidase (TPOA) in autoimmune thyroid disease, gastric parietal cells (PCA) in autoimmune gastritis, transglutaminase (TGA) in celiac disease, and 21-hydroxylase (21-OHA) in autoimmune hypoadrenalism. In addition to the MHC region, we identify SNPs in five susceptibility loci (IFIH1, PTPN22, SH2B3, BACH2, and CTLA4) as significantly associated with more than one autoantibody at a false discovery rate less than 5%. IFIH1/2q24 demonstrated the most unrestricted association, as significant association was demonstrated for PCA, TPOA, GADA, 21-OHA, and IA-2A. In addition, 11 loci were significantly associated with a single autoantibody.