Caesarean section and risk of type 1 diabetes.

AIMS/HYPOTHESIS: Delivery by Caesarean section continues to rise globally and has been associated with the risk of developing type 1 diabetes and the rate of progression from pre-symptomatic stage 1 or 2 type 1 diabetes to symptomatic stage 3 disease. The aim of this study was to examine the association between Caesarean delivery and progression to stage 3 type 1 diabetes in children with pre-symptomatic early-stage type 1 diabetes. METHODS: Caesarean section was examined in 8135 children from the TEDDY study who had an increased genetic risk for type 1 diabetes and were followed from birth for the development of islet autoantibodies and type 1 diabetes. RESULTS: The likelihood of delivery by Caesarean section was higher in children born to mothers with type 1 diabetes (adjusted OR 4.61, 95% CI 3.60, 5.90, p<0.0001), in non-singleton births (adjusted OR 4.35, 95% CI 3.21, 5.88, p<0.0001), in premature births (adjusted OR 1.91, 95% CI 1.53, 2.39, p<0.0001), in children born in the USA (adjusted OR 2.71, 95% CI 2.43, 3.02, p<0.0001) and in children born to older mothers (age group >28-33 years: adjusted OR 1.19, 95% CI 1.04, 1.35, p=0.01; age group >33 years: adjusted OR 1.80, 95% CI 1.58, 2.06, p<0.0001). Caesarean section was not associated with an increased risk of developing pre-symptomatic early-stage type 1 diabetes (risk by age 10 years 5.7% [95% CI 4.6%, 6.7%] for Caesarean delivery vs 6.6% [95% CI 6.0%, 7.3%] for vaginal delivery, p=0.07). Delivery by Caesarean section was associated with a modestly increased rate of progression to stage 3 type 1 diabetes in children who had developed multiple islet autoantibody-positive pre-symptomatic early-stage type 1 diabetes (adjusted HR 1.36, 95% CI 1.03, 1.79, p=0.02). No interaction was observed between Caesarean section and non-HLA SNPs conferring susceptibility for type 1 diabetes. CONCLUSIONS/INTERPRETATION: Caesarean section increased the rate of progression to stage 3 type 1 diabetes in children with pre-symptomatic early-stage type 1 diabetes. DATA AVAILABILITY: Data from the TEDDY study ( https://doi.org/10.58020/y3jk-x087 ) reported here will be made available for request at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repository (NIDDK-CR) Resources for Research (R4R) ( https://repository.niddk.nih.gov/ ).

Early-childhood body mass index and its association with the COVID-19 pandemic, containment measures and islet autoimmunity in children with increased risk for type 1 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to determine whether BMI in early childhood was affected by the COVID-19 pandemic and containment measures, and whether it was associated with the risk for islet autoimmunity. METHODS: Between February 2018 and May 2023, data on BMI and islet autoimmunity were collected from 1050 children enrolled in the Primary Oral Insulin Trial, aged from 4.0 months to 5.5 years of age. The start of the COVID-19 pandemic was defined as 18 March 2020, and a stringency index was used to assess the stringency of containment measures. Islet autoimmunity was defined as either the development of persistent confirmed multiple islet autoantibodies, or the development of one or more islet autoantibodies and type 1 diabetes. Multivariate linear mixed-effect, linear and logistic regression methods were applied to assess the effect of the COVID-19 pandemic and the stringency index on early-childhood BMI measurements (BMI as a time-varying variable, BMI at 9 months of age and overweight risk at 9 months of age), and Cox proportional hazard models were used to assess the effect of BMI measurements on islet autoimmunity risk. RESULTS: The COVID-19 pandemic was associated with increased time-varying BMI (ß = 0.39; 95% CI 0.30, 0.47) and overweight risk at 9 months (ß = 0.44; 95% CI 0.03, 0.84). During the COVID-19 pandemic, a higher stringency index was positively associated with time-varying BMI (ß = 0.02; 95% CI 0.00, 0.04 per 10 units increase), BMI at 9 months (ß = 0.13; 95% CI 0.01, 0.25) and overweight risk at 9 months (ß = 0.23; 95% CI 0.03, 0.43). A higher age-corrected BMI and overweight risk at 9 months were associated with increased risk for developing islet autoimmunity up to 5.5 years of age (HR 1.16; 95% CI 1.01, 1.32 and HR 1.68, 95% CI 1.00, 2.82, respectively). CONCLUSIONS/INTERPRETATION: Early-childhood BMI increased during the COVID-19 pandemic, and was influenced by the level of restrictions during the pandemic. Controlling for the COVID-19 pandemic, elevated BMI during early childhood was associated with increased risk for childhood islet autoimmunity in children with genetic susceptibility to type 1 diabetes.

Consensus guidance for monitoring individuals with islet autoantibody-positive pre-stage 3 type 1 diabetes.

Given the proven benefits of screening to reduce diabetic ketoacidosis (DKA) likelihood at the time of stage 3 type 1 diabetes diagnosis, and emerging availability of therapy to delay disease progression, type 1 diabetes screening programmes are being increasingly emphasised. Once broadly implemented, screening initiatives will identify significant numbers of islet autoantibody-positive (IAb+) children and adults who are at risk of (confirmed single IAb+) or living with (multiple IAb+) early-stage (stage 1 and stage 2) type 1 diabetes. These individuals will need monitoring for disease progression; much of this care will happen in non-specialised settings. To inform this monitoring, JDRF in conjunction with international experts and societies developed consensus guidance. Broad advice from this guidance includes the following: (1) partnerships should be fostered between endocrinologists and primary-care providers to care for people who are IAb+; (2) when people who are IAb+ are initially identified there is a need for confirmation using a second sample; (3) single IAb+ individuals are at lower risk of progression than multiple IAb+ individuals; (4) individuals with early-stage type 1 diabetes should have periodic medical monitoring, including regular assessments of glucose levels, regular education about symptoms of diabetes and DKA, and psychosocial support; (5) interested people with stage 2 type 1 diabetes should be offered trial participation or approved therapies; and (6) all health professionals involved in monitoring and care of individuals with type 1 diabetes have a responsibility to provide education. The guidance also emphasises significant unmet needs for further research on early-stage type 1 diabetes to increase the rigour of future recommendations and inform clinical care.

Clinical care advice for monitoring of islet autoantibody positive individuals with presymptomatic type 1 diabetes.

BACKGROUND/AIM: Type 1 diabetes is an autoimmune disease that involves the development of autoantibodies against pancreatic islet beta-cell antigens, preceding clinical diagnosis by a period of preclinical disease activity. As screening activity to identify autoantibody-positive individuals increases, a rise in presymptomatic type 1 diabetes individuals seeking medical attention is expected. Current guidance on how to monitor these individuals in a safe but minimally invasive way is limited. This article aims to provide clinical guidance for monitoring individuals with presymptomatic type 1 diabetes to reduce the risk of diabetic ketoacidosis (DKA) at diagnosis. METHODS: Expert consensus was obtained from members of the Fr1da, GPPAD, and INNODIA consortia, three European diabetes research groups. The guidance covers both specialist and primary care follow-up strategies. RESULTS: The guidance outlines recommended monitoring approaches based on age, disease stage and clinical setting. Individuals with presymptomatic type 1 diabetes are best followed up in specialist care. For stage 1, biannual assessments of random plasma glucose and HbA1c are suggested for children, while annual assessments are recommended for adolescents and adults. For stage 2, 3-monthly clinic visits with additional home monitoring are advised. The value of repeat OGTT in stage 1 and the use of continuous glucose monitoring in stage 2 are discussed. Primary care is encouraged to monitor individuals who decline specialist care, following the guidance presented. CONCLUSIONS: As type 1 diabetes screening programs become more prevalent, effective monitoring strategies are essential to mitigate the risk of complications such as DKA. This guidance serves as a valuable resource for clinicians, providing practical recommendations tailored to an individual's age and disease stage, both within specialist and primary care settings.

Infection episodes and islet autoantibodies in children at increased risk for type 1 diabetes before and during the COVID-19 pandemic.

OBJECTIVES: To determine the impact of the COVID-19 pandemic on the incidence rates of infection and islet autoimmunity in children at risk for type 1 diabetes. METHODS: 1050 children aged 4 to 7 months with an elevated genetic risk for type 1 diabetes were recruited from Germany, Poland, Sweden, Belgium and the UK. Reported infection episodes and islet autoantibody development were monitored until age 40 months from February 2018 to February 2023. RESULTS: The overall infection rate was 311 (95% Confidence Interval [CI], 304-318) per 100 person years. Infection rates differed by age, country, family history of type 1 diabetes, and period relative to the pandemic. Total infection rates were 321 per 100 person-years (95% CI 304-338) in the pre-pandemic period (until February 2020), 160 (95% CI 148-173) per 100 person-years in the first pandemic year (March 2020-February 2021; P < 0.001) and 337 (95% CI 315-363) per 100 person-years in subsequent years. Similar trends were observed for respiratory and gastrointestinal infections. Islet autoantibody incidence rates were 1.6 (95% CI 1.0-2.4) per 100 person-years in the pre-pandemic period, 1.2 (95% CI 0.8-1.9) per 100 person-years in the first pandemic year (P = 0.46), and 3.4 (95% CI 2.3-4.8) per 100 person-years in subsequent years (P = 0.005 vs. pre-pandemic year; P < 0.001 vs. first pandemic year). CONCLUSIONS: The COVID-19 pandemic was associated with significantly altered infection patterns. Islet autoantibody incidence rates increased two-fold when infection rates returned to pre-pandemic levels.

Children diagnosed with presymptomatic type 1 diabetes through public health screening have milder diabetes at clinical manifestation.

AIMS/HYPOTHESIS: We aimed to determine whether disease severity was reduced at onset of clinical (stage 3) type 1 diabetes in children previously diagnosed with presymptomatic type 1 diabetes in a population-based screening programme for islet autoantibodies. METHODS: Clinical data obtained at diagnosis of stage 3 type 1 diabetes were evaluated in 128 children previously diagnosed with presymptomatic early-stage type 1 diabetes between 2015 and 2022 in the Fr1da study and compared with data from 736 children diagnosed with incident type 1 diabetes between 2009 and 2018 at a similar age in the DiMelli study without prior screening. RESULTS: At the diagnosis of stage 3 type 1 diabetes, children with a prior early-stage diagnosis had lower median HbA1c (51 mmol/mol vs 91 mmol/mol [6.8% vs 10.5%], p<0.001), lower median fasting glucose (5.3 mmol/l vs 7.2 mmol/l, p<0.05) and higher median fasting C-peptide (0.21 nmol/l vs 0.10 nmol/l, p<0.001) compared with children without previous early-stage diagnosis. Fewer participants with prior early-stage diagnosis had ketonuria (22.2% vs 78.4%, p<0.001) or required insulin treatment (72.3% vs 98.1%, p<0.05) and only 2.5% presented with diabetic ketoacidosis at diagnosis of stage 3 type 1 diabetes. Outcomes in children with a prior early-stage diagnosis were not associated with a family history of type 1 diabetes or diagnosis during the COVID-19 pandemic. A milder clinical presentation was observed in children who participated in education and monitoring after early-stage diagnosis. CONCLUSIONS/INTERPRETATION: Diagnosis of presymptomatic type 1 diabetes in children followed by education and monitoring improved clinical presentation at the onset of stage 3 type 1 diabetes.

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.

Progression likelihood score identifies substages of presymptomatic type 1 diabetes in childhood public health screening.

AIMS/HYPOTHESIS: The aim of this study was to develop strategies that identify children from the general population who have late-stage presymptomatic type 1 diabetes and may, therefore, benefit from immune intervention. METHODS: We tested children from Bavaria, Germany, aged 1.75-10 years, enrolled in the Fr1da public health screening programme for islet autoantibodies (n=154,462). OGTT and HbA1c were assessed in children with multiple islet autoantibodies for diagnosis of presymptomatic stage 1 (normoglycaemia) or stage 2 (dysglycaemia) type 1 diabetes. Cox proportional hazards and penalised logistic regression of autoantibody, genetic, metabolic and demographic information were used to develop a progression likelihood score to identify children with stage 1 type 1 diabetes who progressed to stage 3 (clinical) type 1 diabetes within 2 years. RESULTS: Of 447 children with multiple islet autoantibodies, 364 (81.4%) were staged. Undiagnosed stage 3 type 1 diabetes, presymptomatic stage 2, and stage 1 type 1 diabetes were detected in 41 (0.027% of screened children), 30 (0.019%) and 293 (0.19%) children, respectively. The 2 year risk for progression to stage 3 type 1 diabetes was 48% (95% CI 34, 58) in children with stage 2 type 1 diabetes (annualised risk, 28%). HbA1c, islet antigen-2 autoantibody positivity and titre, and the 90 min OGTT value were predictors of progression in children with stage 1 type 1 diabetes. The derived progression likelihood score identified substages corresponding to ≤90th centile (stage 1a, n=258) and >90th centile (stage 1b, n=29; 0.019%) of stage 1 children with a 4.1% (95% CI 1.4, 6.7) and 46% (95% CI 21, 63) 2 year risk of progressing to stage 3 type 1 diabetes, respectively. CONCLUSIONS/INTERPRETATION: Public health screening for islet autoantibodies found 0.027% of children to have undiagnosed clinical type 1 diabetes and 0.038% to have undiagnosed presymptomatic stage 2 or stage 1b type 1 diabetes, with 50% risk to develop clinical type 1 diabetes within 2 years.

Distinguishing activated T regulatory cell and T conventional cells by single-cell technologies.

Resting conventional T cells (Tconv) can be distinguished from T regulatory cells (Treg) by the canonical markers FOXP3, CD25 and CD127. However, the expression of these proteins alters after T-cell activation leading to overlap between Tconv and Treg. The objective of this study was to distinguish resting and antigen-responsive T effector (Tconv) and Treg using single-cell technologies. CD4+ Treg and Tconv cells were stimulated with antigen and responsive and non-responsive populations processed for targeted and non-targeted single-cell RNAseq. Machine learning was used to generate a limited set of genes that could distinguish responding and non-responding Treg and Tconv cells and which was used for single-cell multiplex qPCR and to design a flow cytometry panel. Targeted scRNAseq clearly distinguished the four-cell populations. A minimal set of 27 genes was identified by machine learning algorithms to provide discrimination of the four populations at >95% accuracy. In all, 15 of the genes were validated to be differentially expressed by single-cell multiplex qPCR. Discrimination of responding Treg from responding Tconv could be achieved by a flow cytometry strategy that included staining for CD25, CD127, FOXP3, IKZF2, ITGA4, and the novel marker TRIM which was strongly expressed in Tconv and weakly expressed in both responding and non-responding Treg. A minimal set of genes was identified that discriminates responding and non-responding CD4+ Treg and Tconv cells and, which have identified TRIM as a marker to distinguish Treg by flow cytometry.

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.

Oral insulin immunotherapy in children at risk for type 1 diabetes in a randomised controlled trial.

AIMS/HYPOTHESIS: Oral administration of antigen can induce immunological tolerance. Insulin is a key autoantigen in childhood type 1 diabetes. Here, oral insulin was given as antigen-specific immunotherapy before the onset of autoimmunity in children from age 6 months to assess its safety and immune response actions on immunity and the gut microbiome. METHODS: A phase I/II randomised controlled trial was performed in a single clinical study centre in Germany. Participants were 44 islet autoantibody-negative children aged 6 months to 2.99 years who had a first-degree relative with type 1 diabetes and a susceptible HLA DR4-DQ8-containing genotype. Children were randomised 1:1 to daily oral insulin (7.5 mg with dose escalation to 67.5 mg) or placebo for 12 months using a web-based computer system. The primary outcome was immune efficacy pre-specified as induction of antibody or T cell responses to insulin and measured in a central treatment-blinded laboratory. RESULTS: Randomisation was performed in 44 children. One child in the placebo group was withdrawn after the first study visit and data from 22 insulin-treated and 21 placebo-treated children were analysed. Oral insulin was well tolerated with no changes in metabolic variables. Immune responses to insulin were observed in children who received both insulin (54.5%) and placebo (66.7%), and the trial did not demonstrate an effect on its primary outcome (p = 0.54). In exploratory analyses, there was preliminary evidence that the immune response and gut microbiome were modified by the INS genotype Among children with the type 1 diabetes-susceptible INS genotype (n = 22), antibody responses to insulin were more frequent in insulin-treated (72.7%) as compared with placebo-treated children (18.2%; p = 0.03). T cell responses to insulin were modified by treatment-independent inflammatory episodes. CONCLUSIONS/INTERPRETATION: The study demonstrated that oral insulin immunotherapy in young genetically at-risk children was safe, but was not associated with an immune response as predefined in the trial primary outcome. Exploratory analyses suggested that antibody responses to oral insulin may occur in children with a susceptible INS genotype, and that inflammatory episodes may promote the activation of insulin-responsive T cells. TRIAL REGISTRATION: Clinicaltrials.gov NCT02547519 FUNDING: The main funding source was the German Center for Diabetes Research (DZD e.V.).

Tonic Signaling and Its Effects on Lymphopoiesis of CAR-Armed Hematopoietic Stem and Progenitor Cells.

Long-term survival of adoptively transferred chimeric Ag receptor (CAR) T cells is often limited. Transplantation of hematopoietic stem cells (HSCs) transduced to express CARs could help to overcome this problem as CAR-armed HSCs can continuously deliver CAR+ multicell lineages (e.g., T cells, NK cells). In dependence on the CAR construct, a variable extent of tonic signaling in CAR T cells was reported; thus, effects of CAR-mediated tonic signaling on the hematopoiesis of CAR-armed HSCs is unclear. To assess the effects of tonic signaling, two CAR constructs were established and analyzed 1) a signaling CAR inducing a solid Ag-independent tonic signaling termed CAR-28/ζ and 2) a nonstimulating control CAR construct lacking intracellular signaling domains termed CAR-Stop. Bone marrow cells from immunocompetent mice were isolated, purified for HSC-containing Lin-cKit+ cells or the Lin-cKit+ Sca-1+ subpopulation (Lin-Sca-1+cKit+), and transduced with both CAR constructs. Subsequently, modified bone marrow cells were transferred into irradiated mice, in which they successfully engrafted and differentiated into hematopoietic progenitors. HSCs expressing the CAR-Stop sustained normal hematopoiesis. In contrast, expression of the CAR-28/ζ led to elimination of mature CAR+ T and B cells, suggesting that the CAR-mediated tonic signaling mimics autorecognition via the newly recombined immune receptors in the developing lymphocytes.

Progression from islet autoimmunity to clinical type 1 diabetes is influenced by genetic factors: results from the prospective TEDDY study.

BACKGROUND: Progression time from islet autoimmunity to clinical type 1 diabetes is highly variable and the extent that genetic factors contribute is unknown. METHODS: In 341 islet autoantibody-positive children with the human leucocyte antigen (HLA) DR3/DR4-DQ8 or the HLA DR4-DQ8/DR4-DQ8 genotype from the prospective TEDDY (The Environmental Determinants of Diabetes in the Young) study, we investigated whether a genetic risk score that had previously been shown to predict islet autoimmunity is also associated with disease progression. RESULTS: Islet autoantibody-positive children with a genetic risk score in the lowest quartile had a slower progression from single to multiple autoantibodies (p=0.018), from single autoantibodies to diabetes (p=0.004), and by trend from multiple islet autoantibodies to diabetes (p=0.06). In a Cox proportional hazards analysis, faster progression was associated with an increased genetic risk score independently of HLA genotype (HR for progression from multiple autoantibodies to type 1 diabetes, 1.27, 95% CI 1.02 to 1.58 per unit increase), an earlier age of islet autoantibody development (HR, 0.68, 95% CI 0.58 to 0.81 per year increase in age) and female sex (HR, 1.94, 95% CI 1.28 to 2.93). CONCLUSIONS: Genetic risk scores may be used to identify islet autoantibody-positive children with high-risk HLA genotypes who have a slow rate of progression to subsequent stages of autoimmunity and type 1 diabetes.

Favorable outcome of experimental islet xenotransplantation without immunosuppression in a nonhuman primate model of diabetes.

Transplantation of pancreatic islets for treating type 1 diabetes is restricted to patients with critical metabolic lability resulting from the need for immunosuppression and the shortage of donor organs. To overcome these barriers, we developed a strategy to macroencapsulate islets from different sources that allow their survival and function without immunosuppression. Here we report successful and safe transplantation of porcine islets with a bioartificial pancreas device in diabetic primates without any immune suppression. This strategy should lead to pioneering clinical trials with xenotransplantation for treatment of diabetes and, thereby, represents a previously unidentified approach to efficient cell replacement for a broad spectrum of endocrine disorders and other organ dysfunctions.

Yield of a Public Health Screening of Children for Islet Autoantibodies in Bavaria, Germany.

IMPORTANCE: Public health screening for type 1 diabetes in its presymptomatic stages may reduce disease severity and burden on a population level. OBJECTIVE: To determine the prevalence of presymptomatic type 1 diabetes in children participating in a public health screening program for islet autoantibodies and the risk for progression to clinical diabetes. DESIGN, SETTING, AND PARTICIPANTS: Screening for islet autoantibodies was offered to children aged 1.75 to 5.99 years in Bavaria, Germany, between 2015 and 2019 by primary care pediatricians during well-baby visits. Families of children with multiple islet autoantibodies (presymptomatic type 1 diabetes) were invited to participate in a program of diabetes education, metabolic staging, assessment of psychological stress associated with diagnosis, and prospective follow-up for progression to clinical diabetes until July 31, 2019. EXPOSURES: Measurement of islet autoantibodies. MAIN OUTCOMES AND MEASURES: The primary outcome was presymptomatic type 1 diabetes, defined by 2 or more islet autoantibodies, with categorization into stages 1 (normoglycemia), 2 (dysglycemia), or 3 (clinical) type 1 diabetes. Secondary outcomes were the frequency of diabetic ketoacidosis and parental psychological stress, assessed by the Patient Health Questionnaire-9 (range, 0-27; higher scores indicate worse depression; ≤4 indicates no to minimal depression; >20 indicates severe depression). RESULTS: Of 90 632 children screened (median [interquartile range {IQR}] age, 3.1 [2.1-4.2] years; 48.5% girls), 280 (0.31%; 95% CI, 0.27-0.35) had presymptomatic type 1 diabetes, including 196 (0.22%) with stage 1, 17 (0.02%) with stage 2, 26 (0.03%) with stage 3, and 41 who were not staged. After a median (IQR) follow-up of 2.4 (1.0-3.2) years, another 36 children developed stage 3 type 1 diabetes. The 3-year cumulative risk for stage 3 type 1 diabetes in the 280 children with presymptomatic type 1 diabetes was 24.9% ([95% CI, 18.5%-30.7%]; 54 cases; annualized rate, 9.0%). Two children had diabetic ketoacidosis. Median (IQR) psychological stress scores were significantly increased at the time of metabolic staging in mothers of children with presymptomatic type 1 diabetes (3 [1-7]) compared with mothers of children without islet autoantibodies (2 [1-4]) (P = .002), but declined after 12 months of follow-up (2 [0-4]) (P < .001). CONCLUSIONS AND RELEVANCE: Among children aged 2 to 5 years in Bavaria, Germany, a program of primary care-based screening showed an islet autoantibody prevalence of 0.31%. These findings may inform considerations of population-based screening of children for islet autoantibodies.

Cytoplasmic ends of tetraspanin 7 harbour epitopes recognised by autoantibodies in type 1 diabetes.

AIMS/HYPOTHESIS: The beta cell protein tetraspanin 7 is a target of autoantibodies in individuals with type 1 diabetes. The aim of this study was to identify autoantibody epitope-containing regions and key residues for autoantibody binding. METHODS: Autoantibody epitope regions were identified by immunoprecipitation of luciferase-tagged single or multiple tetraspanin 7 domains using tetraspanin 7 antibody-positive sera. Subsequently, amino acids (AAs) relevant for autoantibody binding were identified by single AA mutations. RESULTS: In tetraspanin 7 antibody-positive sera, antibody binding was most frequent to tetraspanin 7 proteins that contained the NH2-terminal cytoplasmic domain 1 (C1; up to 39%) or COOH-terminal C3 (up to 22%). Binding to C3 was more frequent when the domain was expressed along with the flanking transmembrane domain, suggesting that conformation is likely to be important. Binding to external domains was not observed. Single AA mutations of C3 identified residues Y246, E247 and R239 as critical for COOH-terminal binding of 9/10, 10/10 and 8/10 sera tested, respectively. Mutation of cysteines adjacent to the transmembrane domain at either residues C235 or C236 resulted in both decreased (8/178 and 15/178 individuals, respectively; >twofold decrease) and increased (30/178 and 13/178 individuals, respectively; >twofold increase) binding in participant sera vs wild-type protein. CONCLUSIONS/INTERPRETATION: We hypothesise that conformation and, potentially, modification of protein terminal ends of tetraspanin 7 may be important for autoantibody binding in type 1 diabetes.

Landmark models to define the age-adjusted risk of developing stage 1 type 1 diabetes across childhood and adolescence.

BACKGROUND: Autoimmune diseases are often preceded by an asymptomatic autoantibody-positive phase. In type 1 diabetes, the detection of autoantibodies to pancreatic islet antigens in genetically at-risk children is prognostic for future clinical diabetes. Testing for islet autoantibodies is, therefore, performed in a range of clinical studies. Accurate risk estimates that consider the a priori genetic risk and other risk modifiers are an important component of screening. The age of an individual is an under-appreciated risk modifier. The aim of this study was to provide age-adjusted risk estimates for the development of autoantibodies across childhood in genetically at-risk children. METHODS: The prospective BABYDIAB and BABYDIET studies included 2441 children from birth who had a first-degree relative with type 1 diabetes. Children were born between 1989 and 2006 and were regularly followed from birth for the development of islet autoantibodies and diabetes. A landmark analysis was performed to estimate the risk of islet autoantibodies at birth and at the age 3.5, 6.5 and 12.5 years. Exponential decay curves were fitted for the risk by the age of 20 years. RESULTS: The risk of islet autoantibodies by the age of 20 years was 8%, 4.6%, 2.6% and 0.9%, at the landmark ages of birth, 3.5, 6.5 and 12.5 years, respectively. The short-term risks (within 6 years of follow-up) at these landmark ages were 5.3%, 2.9%, 1.8% and 1%, respectively. The decline in autoantibody risk with age was modelled using a one-phase exponential decay curve (r = 0.99) with a risk half-life of 3.7 years. This risk decay model was remarkably consistent when the outcome was defined as islet autoantibody-positive or multiple islet autoantibody-positive and when the study cohort was stratified by HLA risk genotype. A similar decay model was observed for coeliac disease-associated transglutaminase antibodies in the same cohort. Unlike the risk of developing islet autoantibodies, the rate of developing clinical diabetes in children who were islet autoantibody-positive did not decline with age. CONCLUSION: The risk of developing autoantibodies drops exponentially with age in children with a first-degree relative with type 1 diabetes.

T-cell receptor-α repertoire of CD8+ T cells following allogeneic stem cell transplantation using next-generation sequencing.

Alloreactivity or opportunistic infections following allogeneic stem cell transplantation are difficult to predict and contribute to post-transplantation mortality. How these immune reactions result in changes to the T-cell receptor repertoire remains largely unknown. Using next-generation sequencing, the T-cell receptor alpha (TRα) repertoire of naïve and memory CD8+ T cells from 25 patients who had received different forms of allogeneic transplantation was analyzed. In parallel, reconstitution of the CD8+/CD4+ T-cell subsets was mapped using flow cytometry. When comparing the influence of anti-T-cell therapy, a delay in the reconstitution of the naïve CD8+ T-cell repertoire was observed in patients who received in vivo T-cell depletion using antithymocyte globulin or post-transplantation cyclophosphamide in case of haploidentical transplantation. Sequencing of the TRα identified a repertoire consisting of more dominant clonotypes (>1% of reads) in these patients at 6 and 18 months post transplantation. When comparing donor and recipient, approximately 50% and approximately 80% of the donors' memory repertoire were later retrieved in the naïve and memory CD8+ T-cell receptor repertoire of the recipients, respectively. Although there was a remarkable expansion of single clones observed in the recipients' memory CD8+ TRα repertoire, no clear association between graft-versus-host disease or cytomegalovirus infection and T-cell receptor diversity was identified. A lower TRα diversity was observed in recipients of a cytomegalovirus-seropositive donor (P=0.014). These findings suggest that CD8+ T-cell reconstitution in transplanted patients is influenced by the use of T-cell depletion or immunosuppression and the donor repertoire.

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.

Blood draws up to 3% of blood volume in clinical trials are safe in children.

AIM: Recommendations for maximum blood draw in children range from 1 to 5% despite limited evidence. The aim of the study was to assess the safety of blood draws in children aged six months to 12 years targeting volumes of 3% of total blood volume. METHODS: Children who experienced three-monthly blood draws during participation in one of three investigators initiated clinical trials conducted in our institution were examined. In total, 629 venous blood draws were performed in 141 children. Adverse events and blood counts were assessed. RESULTS: Overall, 608 adverse events were reported. None of these included symptoms that reflected concerns on blood draw volumes or frequency. Anaemia and red cell or haemoglobin measurements outside the normal age range were not observed. A reduction in haemoglobin, haematocrit, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and mean corpuscular volume was noted in children participating in one of the three trials analysed. CONCLUSION: Regular blood draws of up to 3% of total blood volume were not associated with signs of anaemia or hypovolaemia in young children. We suggest that the European recommendations be revised for clinical studies in which children are not exposed to treatments that are associated with anaemia risk.