Antibody detection by agglutination-PCR (ADAP) assays for the analysis of tissue transglutaminase autoantibodies in celiac disease

Background & aims: Tissue transglutaminase autoantibodies (tTGA) are used as diagnostic markers of celiac disease. Different methods have been developed for the detection of tTGA of which enzyme-linked immunosorbent assays (ELISA), radiobinding assays (RBA) and electrochemiluminescence (ECL) assays are the most commonly used. Here we aimed to evaluate a novel antibody detection by agglutination-PCR (ADAP) assay for the detection of tTGA. Methods: Included were 126 children with untreated celiac disease (UCD), 64 disease controls (DC), 21 children with potential celiac disease (PCD), and 1501 children from the general population. Tissue TGA were determined using an automated ADAP assay platform and compared with two RBAs for the detection of IgA-tTG and IgG-tTG, respectively. Results: ADAP detected tTGA in 123/126 (97.6%) UCD children compared with 122/126 (96.8%) using RBA-IgA-tTG and RBA-IgG-tTG (p > 0.9999), respectively. Among DC, ADAP detected 5/64 (7.8%) children with tTGA compared with 4/64 (6.3%) with RBA-IgA-tTG (p > 0.9999) and 8/64 (12.5%) with RBA-IgG-tTG (p = 0.5600), respectively. Tissue TGAs were equally detected in children with PCD in both assays. In the general population, 4/1501 (0.3%) were tTGA positive using ADAP compared with 3/1501 (0.2%) for RBA-IgA-tTG and RBA-IgG-tTG (p > 0.9999), respectively. The area under the curves (AUCs) were 0.998 for ADAP, 0.994 for RBA-IgA-tTG, and 0.999 for RBA-IgG-tTG, respectively. Conclusions: No difference in specificity and sensitivity of tTGA for the diagnosis of celiac disease was reported between ADAP and RBA. ADAP could be recommended as the first-line screening method of larger populations for celiac disease

Long-Term GAD-alum Treatment Effect on Different T-Cell Subpopulations in Healthy Children Positive for Multiple Beta Cell Autoantibodies

Objective. The objective of this study was to explore whether recombinant GAD65 conjugated hydroxide (GAD-alum) treatment affected peripheral blood T-cell subpopulations in healthy children with multiple beta cell autoantibodies. Method. The Diabetes Prevention–Immune Tolerance 2 (DiAPREV-IT 2) clinical trial enrolled 26 children between 4 and 13 years of age, positive for glutamic acid decarboxylase autoantibody (GADA) and at least one other autoantibody (insulin, insulinoma antigen-2, or zinc transporter 8 autoantibody (IAA, IA-2A, or ZnT8A)) at baseline. The children were randomized to two doses of subcutaneously administered GAD-alum treatment or placebo, 30 days apart. Complete blood count (CBC) and immunophenotyping of T-cell subpopulations by flow cytometry were performed regularly during the 24 months of follow-up posttreatment. Cross-sectional analyses were performed comparing lymphocyte and T-cell subpopulations between GAD-alum and placebo-treated subjects. Results. GAD-alum-treated children had lower levels of lymphocytes (109 cells/L) (), T-cells (103 cells/μL) (), T-helper cells (103 cells/μL) (), and cytotoxic T-cells (103 cells/μL) () compared to the placebo-treated children 18 months from first GAD-alum injection. This difference remained 24 months after the first treatment for lymphocytes (), T-cells (), T-helper cells (), and cytotoxic T-cells (). Conclusion. Our findings suggest that levels of total T-cells and T-cell subpopulations declined 18 and 24 months after GAD-alum treatment in healthy children with multiple beta-cell autoantibodies including GADA

Phylogenetic Analysis of HIV-1 Shows Frequent Cross-Country Transmission and Local Population Expansions

International audienceUnderstanding of pandemics depends on characterization of pathogen collections from well-defined and demographically diverse cohorts. Since its emergence in Congo almost a century ago, HIV-1 has geographically spread and genetically diversified into distinct viral subtypes. Phylogenetic analysis can be used to reconstruct the ancestry of the virus to inform on the origin and distribution of subtypes. We sequenced two 3.6 kb amplicons of HIV-1 genomes from 3,197 participants in a clinical trial with consistent and uniform sampling at sites across 35 countries and analyzed our data with another 2,632 genomes that comprehensively reflects the HIV-1 genetic diversity. We used maximum likelihood phylogenetic analysis coupled with geographical information to infer the state of ancestors. The majority of our sequenced genomes (n=2,501) were either pure subtypes (A-D, F, G) or CRF01_AE. The diversity and distribution of subtypes across geographical regions differed; United States showed the most homogenous subtype population, whereas African samples were most diverse. We delineated transmission of the four most prevalent subtypes in our dataset (A, B, C, and CRF01_AE), and our results suggest both continuous and frequent transmission of HIV-1 over country borders, as well as single transmission events being the seed of endemic population expansions. Overall, we show that coupling of genetic and geographical information of HIV-1 can be used to understand origin and spread of pandemic pathogens

Gestational diabetes mellitus is associated with TCF7L2 gene polymorphisms independent of HLA-DQB1*0602 genotypes and islet cell autoantibodies.

Aims: To test whether the TCF7L2 gene was associated with gestational diabetes, whether the association between TCF7L2 and gestational diabetes was independent of HLA-DQB1*0602 and islet cell autoantibodies, as well as maternal age, number of pregnancies, family history of diabetes and the HLA-DQB1 genotypes, and to test whether the distribution of HLA-DQB1 alleles was affected by country of birth. Methods: We genotyped the rs7903146, rs12255372 and rs7901695 single nucleotide polymorphisms of the TCF7L2 gene in 826 mothers with gestational diabetes and in 1185 healthy control subjects in the Diabetes Prediction in Skåne Study. The mothers were also typed for HLA-DQB1 genotypes and tested for islet cell autoantibodies against GAD65, insulinoma-associated antigen-2 and insulin. Results: The heterozygous genotypes CT, GT and TC of the rs7903146 (T is risk for Type 2 diabetes), rs12255372 (T is risk for Type 2 diabetes) and rs7901695 (C is risk for Type 2 diabetes), respectively, as well as the homozygous genotypes TT, TT and CC of the rs7903146, rs12255372 and rs7901695, respectively, were strongly associated with gestational diabetes (P < 0.0001). These associations remained statistically significant after adjusting for maternal age, number of pregnancies, family history of diabetes and HLA-DQ genotypes and were independent of the presence of islet cell autoantibodies. No interaction was observed between TCF7L2 and HLA-DQB1*0602, which was shown to be negatively associated with gestational diabetes in mothers born in Sweden (P = 0.010). Conclusions: The TCF7L2 was associated with susceptibility for gestational diabetes independently of the presence of HLA-DQB1*0602 and islet cell autoantibodies and other factors such as maternal age, number of pregnancies, family history of diabetes and other HLA-DQ genotypes. The HLA-DQB1*0602 was negatively associated with gestational diabetes in mothers born in Sweden

Metabolomics Profiling of Patients With A-β+ Ketosis-Prone Diabetes During Diabetic Ketoacidosis

When stable and near-normoglycemic, patients with "A-β+" ketosis-prone diabetes (KPD) manifest accelerated leucine catabolism and blunted ketone oxidation, which may underlie their proclivity to develop diabetic ketoacidosis (DKA). To understand metabolic derangements in A-β+ KPD patients during DKA, we compared serum metabolomics profiles of adults during acute hyperglycemic crises, without (n = 21) or with (n = 74) DKA, and healthy control subjects (n = 17). Based on 65 kDa GAD islet autoantibody status, C-peptide, and clinical features, 53 DKA patients were categorized as having KPD and 21 type 1 diabetes (T1D); 21 nonketotic patients were categorized as having type 2 diabetes (T2D). Patients with KPD and patients with T1D had higher counterregulatory hormones and lower insulin-to-glucagon ratio than patients with T2D and control subjects. Compared with patients withT2D and control subjects, patients with KPD and patients with T1D had lower free carnitine and higher long-chain acylcarnitines and acetylcarnitine (C2) but lower palmitoylcarnitine (C16)-to-C2 ratio; a positive relationship between C16 and C2 but negative relationship between carnitine and β-hydroxybutyrate (BOHB); higher branched-chain amino acids (BCAAs) and their ketoacids but lower ketoisocaproate (KIC)-to-Leu, ketomethylvalerate (KMV)-to-Ile, ketoisovalerate (KIV)-to-Val, isovalerylcarnitine-to-KIC+KMV, propionylcarnitine-to-KIV+KMV, KIC+KMV-to-C2, and KIC-to-BOHB ratios; and lower glutamate and 3-methylhistidine. These data suggest that during DKA, patients with KPD resemble patients with T1D in having impaired BCAA catabolism and accelerated fatty acid flux to ketones-a reversal of their distinctive BCAA metabolic defect when stable. The natural history of A-β+ KPD is marked by chronic but varying dysregulation of BCAA metabolism

Multiplex agglutination-PCR (ADAP) autoantibody assays compared to radiobinding autoantibodies in type 1 diabetes and celiac disease

Multiplex Antibody-Detection by Agglutination-PCR (ADAP) assay was compared to singleplex standard radiobinding assays (RBA) to detect autoantibodies against insulin (IAA), GAD65 (GADA), islet antigen-2 (IA-2A), ZnT8 (ZnT8A) and tissue transglutaminase (TGA). Serum samples from 272 (114F/158M), 15-73 years of age healthy controls and 227 (109F/118M) newly diagnosed type 1 diabetes children, 1-11 years of age, were analyzed in both assay systems.The original WHO standard 97/550 and in-house reference standards for RBA were compared to ADAP. The ADAP and RBA generated parallel reference standards in all assays except TGA. Lower detection limits were observed in the ADAP assay for GADA,IAA and ZnT8A, markedly for TGA, but not for IA-2A. The Receiver Operating Characteristics (ROC) curve AUC analyses for pairwise comparison of ADAP with RBA showed no difference for GADA (n.s.), ADAP greater AUC for IAA (p = 0.005), RBA greater AUC for IA-2A (p = 0.0004) and ZnT8A (p < 0.0001) while ADAP TGA had a greater AUC compared to both RBA TGA-IgG (p < 0.0001) and TGA-IgA (p < 0.0001) . These data suggest that the ADAP and RBA assays are comparable with equal performance for GADA, better ADAP performance for IAA while the RBA showed better performance in both IA-2A and ZnT8A associated with greater heterogeneity in autoantibody levels. The simultaneous analysis of 5 different autoantibodies by ADAP in sample volume reduced to only 4 μL and at an increased lower detection limit in all assays except IA-2A makes the ADAP automated autoantibody assay a distinct advantage for high throughput screening

Metabolite-related dietary patterns and the development of islet autoimmunity

The role of diet in type 1 diabetes development is poorly understood. Metabolites, which reflect dietary response, may help elucidate this role. We explored metabolomics and lipidomics differences between 352 cases of islet autoimmunity (IA) and controls in the TEDDY (The Environmental Determinants of Diabetes in the Young) study. We created dietary patterns reflecting pre-IA metabolite differences between groups and examined their association with IA. Secondary outcomes included IA cases positive for multiple autoantibodies (mAb+). The association of 853 plasma metabolites with outcomes was tested at seroconversion to IA, just prior to seroconversion, and during infancy. Key compounds in enriched metabolite sets were used to create dietary patterns reflecting metabolite composition, which were then tested for association with outcomes in the nested case-control subset and the full TEDDY cohort. Unsaturated phosphatidylcholines, sphingomyelins, phosphatidylethanolamines, glucosylceramides, and phospholipid ethers in infancy were inversely associated with mAb+ risk, while dicarboxylic acids were associated with an increased risk. An infancy dietary pattern representing higher levels of unsaturated phosphatidylcholines and phospholipid ethers, and lower sphingomyelins was protective for mAb+ in the nested case-control study only. Characterization of this high-risk infant metabolomics profile may help shape the future of early diagnosis or prevention efforts. © 2019, The Author(s)

Psychological manifestations of celiac disease autoimmunity in young children

BACKGROUND AND OBJECTIVES: Psychological symptoms can be associated with celiac disease; abstract however, this association has not been studied prospectively in a pediatric cohort. We examined mother report of psychological functioning in children persistently positive for tissue transglutaminase autoantibodies (tTGA), defined as celiac disease autoimmunity (CDA), compared with children without CDA in a screening population of genetically at-risk children. We also investigated differences in psychological symptoms based on mothers' awareness of their child's CDA status. METHODS: The Environmental Determinants of Diabetes in the Young study followed 8676 children to identify triggers of type 1 diabetes and celiac disease. Children were tested for tTGA beginning at 2 years of age. The Achenbach Child Behavior Checklist assessed child psychological functioning at 3.5 and 4.5 years of age. RESULTS: At 3.5 years, 66 mothers unaware their child had CDA reported more child anxiety and depression, aggressive behavior, and sleep problems than 3651 mothers of children without CDA (all Ps ≤ .03). Unaware-CDA mothers also reported more child anxiety and depression, withdrawn behavior, aggressive behavior, and sleep problems than 440 mothers aware of their child's CDA status (all Ps ≤.04). At 4.5 years, there were no differences. CONCLUSIONS: In 3.5-year-old children, CDA is associated with increased reports of child depression and anxiety, aggressive behavior, and sleep problems when mothers are unaware of their child's CDA status. Mothers' knowledge of their child's CDA status is associated with fewer reports of psychological symptoms, suggesting that awareness of the child's tTGA test results affects reporting of symptoms

Complement gene variants in relation to autoantibodies to beta cell specific antigens and type 1 diabetes in the TEDDY Study

A total of 15 SNPs within complement genes and present on the ImmunoChip were analyzed in The Environmental Determinants of Diabetes in the Young (TEDDY) study. A total of 5474 subjects were followed from three months of age until islet autoimmunity (IA: n = 413) and the subsequent onset of type 1 diabetes (n = 115) for a median of 73 months (IQR 54-91). Three SNPs within ITGAM were nominally associated (p < 0.05) with IA: rs1143678 [Hazard ratio; HR 0.80; 95% CI 0.66-0.98; p = 0.032], rs1143683 [HR 0.80; 95% CI 0.65-0.98; p = 0.030] and rs4597342 [HR 1.16; 95% CI 1.01-1.32; p = 0.041]. When type 1 diabetes was the outcome, in DR3/4 subjects, there was nominal significance for two SNPs: rs17615 in CD21 [HR 1.52; 95% CI 1.05-2.20; p = 0.025] and rs4844573 in C4BPA [HR 0.63; 95% CI 0.43-0.92; p = 0.017]. Among DR4/4 subjects, rs2230199 in C3 was significantly associated [HR 3.20; 95% CI 1.75-5.85; p = 0.0002, uncorrected] a significance that withstood Bonferroni correction since it was less than 0.000833 (0.05/60) in the HLA-specific analyses. SNPs within the complement genes may contribute to IA, the first step to type 1 diabetes, with at least one SNP in C3 significantly associated with clinically diagnosed type 1 diabetes

Identification of infants with increased type 1 diabetes genetic risk for enrollment into Primary Prevention Trials-GPPAD-02 study design and first results

Primary prevention of type 1 diabetes (T1D) requires intervention in genetically at-risk infants. The Global Platform for the Prevention of Autoimmune Diabetes (GPPAD) has established a screening program, GPPAD-02, that identifies infants with a genetic high risk of T1D, enrolls these into primary prevention trials, and follows the children for beta-cell autoantibodies and diabetes. Genetic testing is offered either at delivery, together with the regular newborn testing, or at a newborn health care visits before the age of 5 months in regions of Germany (Bavaria, Saxony, Lower Saxony), UK (Oxford), Poland (Warsaw), Belgium (Leuven), and Sweden (Region Skåne). Seven clinical centers will screen around 330 000 infants. Using a genetic score based on 46 T1D susceptibility single-nucleotide polymorphisms (SNPs) or three SNPS and a first-degree family history for T1D, infants with a high (>10%) genetic risk for developing multiple beta-cell autoantibodies by the age of 6 years are identified. Screening from October 2017 to December 2018 was performed in 50 669 infants. The prevalence of high genetic risk for T1D in these infants was 1.1%. Infants with high genetic risk for T1D are followed up and offered to participate in a randomized controlled trial aiming to prevent beta-cell autoimmunity and T1D by tolerance induction with oral insulin. The GPPAD-02 study provides a unique path to primary prevention of beta-cell autoimmunity in the general population. The eventual benefit to the community, if successful, will be a reduction in the number of children developing beta-cell autoimmunity and T1D.status: publishe