SARS-CoV-2 Infection and Development of Islet Autoimmunity in Early Childhood.

Importance: The incidence of diabetes in childhood has increased during the COVID-19 pandemic. Elucidating whether SARS-CoV-2 infection is associated with islet autoimmunity, which precedes type 1 diabetes onset, is relevant to disease etiology and future childhood diabetes trends. Objective: To determine whether there is a temporal relationship between SARS-CoV-2 infection and the development of islet autoimmunity in early childhood. Design, Setting, and Participants: Between February 2018 and March 2021, the Primary Oral Insulin Trial, a European multicenter study, enrolled 1050 infants (517 girls) aged 4 to 7 months with a more than 10% genetically defined risk of type 1 diabetes. Children were followed up through September 2022. Exposure: SARS-CoV-2 infection identified by SARS-CoV-2 antibody development in follow-up visits conducted at 2- to 6-month intervals until age 2 years from April 2018 through June 2022. Main Outcomes and Measures: The development of multiple (≥2) islet autoantibodies in follow-up in consecutive samples or single islet antibodies and type 1 diabetes. Antibody incidence rates and risk of developing islet autoantibodies were analyzed. Results: Consent was obtained for 885 (441 girls) children who were included in follow-up antibody measurements from age 6 months. SARS-CoV-2 antibodies developed in 170 children at a median age of 18 months (range, 6-25 months). Islet autoantibodies developed in 60 children. Six of these children tested positive for islet autoantibodies at the same time as they tested positive for SARS-CoV-2 antibodies and 6 at the visit after having tested positive for SARS-CoV-2 antibodies. The sex-, age-, and country-adjusted hazard ratio for developing islet autoantibodies when the children tested positive for SARS-CoV-2 antibodies was 3.5 (95% CI, 1.6-7.7; P = .002). The incidence rate of islet autoantibodies was 3.5 (95% CI, 2.2-5.1) per 100 person-years in children without SARS-CoV-2 antibodies and 7.8 (95% CI, 5.3-19.0) per 100 person-years in children with SARS-CoV-2 antibodies (P = .02). Islet autoantibody risk in children with SARS-CoV-2 antibodies was associated with younger age (<18 months) of SARS-CoV-2 antibody development (HR, 5.3; 95% CI, 1.5-18.3; P = .009). Conclusion and relevance: In young children with high genetic risk of type 1 diabetes, SARS-CoV-2 infection was temporally associated with the development of islet autoantibodies.

Autoantibodies against ATP4A are a feature of the abundant autoimmunity that develops in first-degree relatives of patients with type 1 diabetes.

OBJECTIVE: Type 1 diabetes is associated with autoantibodies to different organs that include the gut. The objective of the study was to determine the risk of developing gastric parietal cell autoimmunity in relation to other autoimmunity in individuals with a family history of type 1 diabetes. METHODS: Autoantibodies to the parietal cell autoantigen, H+ /K+ ATPase subunit A (ATP4A) was measured in 2218 first-degree relatives of patients with type 1 diabetes, who were prospectively followed from birth for a median of 14.5 years. All were also tested regularly for the development of islet autoantibodies, transglutaminase autoantibodies, and thyroid peroxidase autoantibodies. RESULTS: The cumulative risk to develop ATP4A autoantibodies was 8.1% (95% CI, 6.6-9.6) by age 20 years with a maximum incidence observed at age 2 years. Risk was increased in females (HR, 1.9; 95% CI, 1.3-2.8; p = 0.0004), relatives with the HLA DR4-DQ8/DR4-DQ8 genotype (HR, 3.4; 95% CI, 1.9-5.9; p < 0.0001) and in participants who also had thyroid peroxidase autoantibodies (HR, 3.7; 95% CI, 2.5-5.5; p < 0.0001). Risk for at least one of ATP4A-, islet-, transglutaminase-, or thyroid peroxidase-autoantibodies was 24.7% (95% CI, 22.6-26.7) by age 20 years and was 47.3% (95% CI, 41.3-53.3) in relatives who had an HLA DR3/DR4-DQ8, DR4-DQ8/DR4-DQ8, or DR3/DR3 genotype (p < 0.0001 vs. other genotypes). CONCLUSIONS: Relatives of patients with type 1 diabetes who have risk genotypes are at very high risk for the development of autoimmunity against gastric and other organs.

3 Screen ELISA for High-Throughput Detection of Beta Cell Autoantibodies in Capillary Blood.

BACKGROUND: Testing for beta cell autoantibodies is used for wide-scale identification of early stages of type 1 diabetes. This requires suitable screening assays. We aimed to establish screening that utilized a first step assay (3 Screen) able to detect autoantibodies to the target antigens glutamic acid decarboxylase-65 (GAD), insulinoma-associated antigen 2 (IA-2), and zinc transporter 8 (ZnT8) to identify children positive for multiple beta cell autoantibodies. METHODS: An ELISA format was used where plates were coated with a mixture of recombinant GAD, IA-2, and ZnT8325W/R-dimer molecules. The performance was determined in venous blood from 686 first-degree relatives of patients with type 1 diabetes, and 200 patients at onset of type 1 diabetes, and applied as a screening assay in capillary blood from 33,639 general population children. RESULTS: The 3 Screen assay sensitivity for detecting autoantibody-positive patients at onset of type 1 diabetes was similar to that achieved by separate radiobinding assays (RBAs) for antibodies to GAD, IA-2, and ZnT8. Results in venous and capillary serum were correlated (R = 0.987). At a threshold corresponding to the 98th centile (29.1 U/mL) of all 33,639 capillary samples, the 3 Screen was positive in 123 samples with two or more RBA-positive antibodies to insulin, GAD, IA-2, or ZnT8, 146 with one antibody, and 479 that were RBA negative for beta cell autoantibodies. CONCLUSION: A 3 Screen ELISA was developed that was suitable for first step screening of multiple beta cell autoantibodies in capillary blood.

3 Screen islet cell autoantibody ELISA: A sensitive and specific ELISA for the combined measurement of autoantibodies to GAD65, to IA-2 and to ZnT8.

3 Screen, a new ELISA for the combined measurement of autoantibodies to GAD65, to IA-2 and to ZnT8, has been developed and evaluated. In the assay serum samples were incubated (overnight; 2-8°C) in ELISA plate wells coated with GAD65, IA-2 and ZnT8 followed by a wash step and incubation with biotinylated GAD65, IA-2 and ZnT8 (1h; 2-8°C,). The assay was completed by addition of streptavidin-peroxidase and tetramethylbenzidine. Samples tested in the 3 Screen were also analysed in ELISAs and radiobinding assays for the three individual autoantibodies. 129/132 (98%) samples from newly diagnosed T1DM children and 1/100 non-diabetic children controls were positive in 3 Screen. There was good agreement between 3 Screen and the individual autoantibody assays. Dilution of positive samples showed good linearity characteristics. In the 2015 Islet Autoantibody Standardization Program 3 Screen achieved 94% sensitivity, 95.6% specificity and 0.948 area under curve by ROC analysis. 3 Screen provides a simple and sensitive method for combined measurement of three major diabetes associated autoantibodies in a single sample. The assay should be a useful tool for large scale population screening for individuals at risk of developing T1DM.

Capillary blood islet autoantibody screening for identifying pre-type 1 diabetes in the general population: design and initial results of the Fr1da study.

INTRODUCTION: Type 1 diabetes can be diagnosed at an early presymptomatic stage by the detection of islet autoantibodies. The Fr1da study aims to assess whether early staging of type 1 diabetes (1) is feasible at a population-based level, (2) prevents severe metabolic decompensation observed at the clinical manifestation of type 1 diabetes and (3) reduces psychological distress through preventive teaching and care. METHODS AND ANALYSIS: Children aged 2-5 years in Bavaria, Germany, will be tested for the presence of multiple islet autoantibodies. Between February 2015 and December 2016, 100 000 children will be screened by primary care paediatricians. Islet autoantibodies are measured in capillary blood samples using a multiplex three-screen ELISA. Samples with ELISA results >97.5th centile are retested using reference radiobinding assays. A venous blood sample is also obtained to confirm the autoantibody status of children with at least two autoantibodies. Children with confirmed multiple islet autoantibodies are diagnosed with pre-type 1 diabetes. These children and their parents are invited to participate in an education and counselling programme at a local diabetes centre. Depression and anxiety, and burden of early diagnosis are also assessed. RESULTS: Of the 1027 Bavarian paediatricians, 39.3% are participating in the study. Overall, 26 760 children have been screened between February 2015 and November 2015. Capillary blood collection was sufficient in volume for islet autoantibody detection in 99.46% of the children. The remaining 0.54% had insufficient blood volume collected. Of the 26 760 capillary samples tested, 0.39% were positive for at least two islet autoantibodies. DISCUSSION: Staging for early type 1 diabetes within a public health setting appears to be feasible. The study may set new standards for the early diagnosis of type 1 diabetes and education. ETHICS DISSEMINATION: The study was approved by the ethics committee of Technische Universität München (Nr. 70/14).

Islet autoantibody phenotypes and incidence in children at increased risk for type 1 diabetes.

AIMS/HYPOTHESIS: Autoantibodies that precede type 1 diabetes frequently develop in early childhood and target distinct beta cell proteins. The aim of this study was to determine the heterogeneity of islet autoantibody development and fate. METHODS: The ages of development of insulin autoantibodies (IAA) and GAD autoantibodies (GADA), followed by multiple islet autoantibodies and progression to diabetes were examined in 2,441 children participating in two German birth cohorts. RESULTS: In 218 children who developed islet autoantibodies, the first islet autoantibody-positive sample was characterised by single IAA in 80 (37%), multiple islet autoantibodies in 68 (31%) and single GADA in 63 (29%) children. Of the children who were single antibody positive at seroconversion, 35 (44%) IAA-positive and 15 (24%) GADA-positive children developed multiple islet autoantibodies. Single persistent antibodies had heterogeneous affinities; GADA were also heterogeneous in their binding to N-terminally truncated GAD65 and in an ELISA. Progression to diabetes occurred in >50% of children within 10 years in all groups that developed multiple islet autoantibodies and in 44% of children with persistent single high-affinity IAA or persistent single GADA that were positive in both a radiobinding assay and ELISA. The earliest autoantibody development was seen in children with single IAA that progressed to multiple islet autoantibodies or in those with persistent high-affinity single IAA, with a sharp peak in incidence observed at age 9 months. The peak incidence occurred at age 2 years for children who underwent seroconversion directly to multiple islet autoantibodies and at 5 years for children who first seroconverted to GADA and subsequently developed other autoantibodies. Seroconversion to low-affinity IAA or persistent single GADA occurred at a low incidence after the age of 9 months. CONCLUSIONS/INTERPRETATION: Children of different ages have differing susceptibilities to autoimmunisation against specific beta cell autoantigens.

Continuous rise of insulin resistance before and after the onset of puberty in children at increased risk for type 1 diabetes - a cross-sectional analysis.

BACKGROUND: Insulin resistance has been postulated to be linked to the frequent onset of type 1 diabetes (T1D) during puberty. Very few studies have investigated the time course of insulin resistance in childhood. To address the question of how insulin resistance develops with age and how this is related to puberty onset, we examined insulin resistance and pubertal development over time in children at increased risk for T1D. METHODS: Homeostasis model assessment of insulin resistance (HOMA-IR) was measured in 1848 fasting samples of 1177 children (aged 5-15 years) in a cross-sectional analysis. All children had a first degree relative with T1D, 120 developed islet autoantibodies. Pubertal development was determined by Tanner staging. RESULTS: Insulin resistance rose continuously from age 5 to 13 years in girls and from age 5 to 14 years in boys with an average increase of 0.09 (95 % confidence interval [CI]: 0.08-0.10) per year for girls and 0.07 (95 % CI: 0.06-0.08) for boys. The rise preceded the onset of puberty (Tanner stage 2), which was reported between 10 and 12 years of age in 80.4 % of the children (mean age: 11.2 ± 0.06 years). No difference was seen between children with or without islet autoantibodies. CONCLUSIONS: There was a constant age-dependent rise of insulin resistance during childhood without observed associations to the onset of puberty or the presence of islet autoimmunity in children at increased risk for T1D. Our data show that insulin resistance emerges well before the initiation of physical changes of puberty.

IA-2 autoantibody affinity in children at risk for type 1 diabetes.

Autoantibodies to insulinoma-associated protein 2 (IA-2A) are associated with increased risk for type 1 diabetes. Here we examined IA-2A affinity and epitope specificity to assess heterogeneity in response intensity in relation to pathogenesis and diabetes risk in 50 children who were prospectively followed from birth. At first IA-2A appearance, affinity ranged from 10(7) to 10(11)L/mol and was high (>1.0×10(9)L/mol) in 41 (82%) children. IA-2A affinity was not associated with epitope specificity or HLA class II haplotype. On follow-up, affinity increased or remained high, and IA-2A were commonly against epitopes within the protein tyrosine phosphatase-like IA-2 domain and the homologue protein IA-2ß. IA-2A were preceded or accompanied by other islet autoantibodies in 49 (98%) children, of which 34 progressed to diabetes. IA-2A affinity did not stratify diabetes risk. In conclusion, the IA-2A response in children is intense with rapid maturation against immunogenic epitopes and a strong association with diabetes development.