Circulating β cell-specific CD8+ T cells restricted by high-risk HLA class I molecules show antigen experience in children with and at risk of type 1 diabetes

In type 1 diabetes (T1D), autoreactive cytotoxic CD8+ T cells are implicated in the destruction of insulin-producing β cells. The HLA-B*3906 and HLA-A*2402 class I genes confer increased risk and promote early disease onset, suggesting that CD8+ T cells that recognize peptides presented by these class I molecules on pancreatic β cells play a pivotal role in the autoimmune response. We examined the frequency and phenotype of circulating preproinsulin (PPI)-specific and insulin B (InsB)-specific CD8+ T cells in HLA-B*3906+ children newly diagnosed with T1D and in high-risk HLA-A*2402+ children before the appearance of disease-specific autoantibodies and before diagnosis of T1D. Antigen-specific CD8+ T cells were detected using human leucocyte antigen (HLA) class I tetramers and flow cytometry was used to assess memory status. In HLA-B*3906+ children with T1D, we observed an increase in PPI5-12 -specific transitional memory CD8+ T cells compared to non-diabetic, age- and HLA-matched subjects. Furthermore, PPI5-12 -specific CD8+ T cells in HLA-B*3906+ children with T1D showed a significantly more antigen-experienced phenotype compared to polyclonal CD8+ T cells. In longitudinal samples from high-risk HLA-A*2402+ children, the percentage of terminal effector cells within the InsB15-24 -specific CD8+ T cells was increased before diagnosis relative to samples taken before the appearance of autoantibodies. This is the first study, to our knowledge, to report HLA-B*3906-restricted autoreactive CD8+ T cells in T1D. Collectively, our results provide evidence that β cell-reactive CD8+ T cells restricted by disease-associated HLA class I molecules display an antigen-experienced phenotype and acquire enhanced effector function during the period leading to clinical diagnosis, implicating these cells in driving disease.

Longitudinal Pattern of First-Phase Insulin Response Is Associated With Genetic Variants Outside the Class II HLA Region in Children With Multiple Autoantibodies

A declining first-phase insulin response (FPIR) is associated with positivity for multiple islet autoantibodies, irrespective of class II HLA DR-DQ genotype. We examined the associations of FPIR with genetic variants outside the HLA DR-DQ region in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study in children with and without multiple autoantibodies. Association between FPIR and class I alleles A*24 and B*39 and eight single nucleotide polymorphisms outside the HLA region were analyzed in 438 children who had one or more FPIR results available after seroconversion. Hierarchical linear mixed models were used to analyze repeated measurements of FPIR. In children with multiple autoantibodies, the change in FPIR over time was significantly different between those with various PTPN2 (rs45450798), FUT2 (rs601338), CTSH (rs3825932), and IKZF4 (rs1701704) genotypes in at least one of the models. In general, children carrying susceptibility alleles for type 1 diabetes experienced a more rapid decline in insulin secretion compared with children without susceptibility alleles. The presence of the class I HLA A*24 allele was also associated with a steeper decline of FPIR over time in children with multiple autoantibodies. Certain genetic variants outside the class II HLA region may have a significant impact on the longitudinal pattern of FPIR.

Type 1 diabetes linked PTPN22 gene polymorphism is associated with the frequency of circulating regulatory T cells

Dysfunction of FOXP3-positive regulatory T cells (Tregs) likely plays a major role in the pathogenesis of multiple autoimmune diseases including type 1 diabetes (T1D). Whether genetic polymorphisms associated with the risk of autoimmune diseases affect Treg frequency or function is currently unclear. Here, we analysed the effect of T1D-associated major HLA class II haplotypes and seven single nucleotide polymorphisms in six non-HLA genes [INS (rs689), PTPN22 (rs2476601), IL2RA (rs12722495 and rs2104286), PTPN2 (rs45450798), CTLA4 (rs3087243), and ERBB3 (rs2292239)] on peripheral blood Treg frequencies. These were determined by flow cytometry in 65 subjects who had progressed to T1D, 86 islet autoantibody-positive at-risk subjects, and 215 islet autoantibody-negative healthy controls. The PTPN22 rs2476601 risk allele A was associated with an increase in total (p = 6 × 10^-6 ) and naïve (p = 4 × 10^-5 ) CD4+CD25+CD127lowFOXP3+ Treg frequencies. These findings were validated in a separate cohort comprising ten trios of healthy islet autoantibody-negative children carrying each of the three PTPN22 rs2476601 genotypes AA, AG, and GG (p = 0.005 for total and p = 0.03 for naïve Tregs, respectively). In conclusion, our analysis implicates the autoimmune PTPN22 rs2476601 risk allele A in controlling the frequency of Tregs in human peripheral blood.

Circulating metabolites in progression to islet autoimmunity and type 1 diabetes

AIMS/HYPOTHESIS

Metabolic dysregulation may precede the onset of type 1 diabetes. However, these metabolic disturbances and their specific role in disease initiation remain poorly understood. In this study, we examined whether children who progress to type 1 diabetes have a circulatory polar metabolite profile distinct from that of children who later progress to islet autoimmunity but not type 1 diabetes and a matched control group.

METHODS

We analysed polar metabolites from 415 longitudinal plasma samples in a prospective cohort of children in three study groups: those who progressed to type 1 diabetes; those who seroconverted to one islet autoantibody but not to type 1 diabetes; and an antibody-negative control group. Metabolites were measured using two-dimensional GC high-speed time of flight MS.

RESULTS

In early infancy, progression to type 1 diabetes was associated with downregulated amino acids, sugar derivatives and fatty acids, including catabolites of microbial origin, compared with the control group. Methionine remained persistently upregulated in those progressing to type 1 diabetes compared with the control group and those who seroconverted to one islet autoantibody. The appearance of islet autoantibodies was associated with decreased glutamic and aspartic acids.

CONCLUSIONS/INTERPRETATION

Our findings suggest that children who progress to type 1 diabetes have a unique metabolic profile, which is, however, altered with the appearance of islet autoantibodies. Our findings may assist with early prediction of the disease.

LFRET, a novel rapid assay for anti-tissue transglutaminase antibody detection

The diagnosis of celiac disease (CD) is currently based on serology and intestinal biopsy, with detection of anti-tissue transglutaminase (tTG) IgA antibodies recommended as the first-line test. Emphasizing the increasing importance of serological testing, new guidelines and evidence suggest basing the diagnosis solely on serology without confirmatory biopsy. Enzyme immunoassays (EIAs) are the established approach for anti-tTG antibody detection, with the existing point-of-care (POC) tests lacking sensitivity and/or specificity. Improved POC methods could help reduce the underdiagnosis and diagnostic delay of CD. We have previously developed rapid homogenous immunoassays based on time-resolved Förster resonance energy transfer (TR-FRET), and demonstrated their suitability in serodiagnostics with hanta- and Zika virus infections as models. In this study, we set out to establish a protein L -based TR-FRET assay (LFRET) for the detection of anti-tTG antibodies. We studied 74 patients with biopsy-confirmed CD and 70 healthy controls, with 1) the new tTG-LFRET assay, and for reference 2) a well-established EIA and 3) an existing commercial POC test. IgG depletion was employed to differentiate between anti-tTG IgA and IgG positivity. The sensitivity and specificity of the first-generation tTG-LFRET POC assay in detection of CD were 87.8% and 94.3%, respectively, in line with those of the reference POC test. The sensitivity and specificity of EIA were 95.9% and 91.9%, respectively. This study demonstrates the applicability of LFRET to serological diagnosis of autoimmune diseases in general and of CD in particular.

Distinct migratory pattern of naive and effector T cells through the blood-CSF barrier following Echovirus 30 infection

Background

Echovirus 30 (E-30) is one of the most frequently isolated pathogens in aseptic meningitis worldwide. To gain access to the central nervous system (CNS), E-30 and immune cells have to cross one of the two main barriers of the CNS, the epithelial blood–cerebrospinal fluid barrier (BCSFB) or the endothelial blood–brain barrier (BBB). In an in vitro model of the BCSFB, it has been shown that E-30 can infect human immortalized brain choroid plexus papilloma (HIBCPP) cells.

Methods

In this study we investigated the migration of different T cell subpopulations, naive and effector T cells, through HIBCPP cells during E-30 infection. Effects of E-30 infection and the migration process were evaluated via immunofluorescence and flow cytometry analysis, as well as transepithelial resistance and dextran flux measurement.

Results

Th1 effector cells and enterovirus-specific effector T cells migrated through HIBCPP cells more efficiently than naive CD4⁺ T cells following E-30 infection of HIBCPP cells. Among the different naive T cell populations, CD8⁺ T cells crossed the E-30-infected HIBCPP cell layer in a significantly higher number than CD4⁺ T cells. A large amount of effector T cells also remained attached to the basolateral side of the HIBCPP cells compared with naive T cells. Analysis of HIBCPP barrier function showed significant alteration after E-30 infection and trans- as well as paracellular migration of T cells independent of the respective subpopulation. Morphologic analysis of migrating T cells revealed that a polarized phenotype was induced by the chemokine CXCL12, but reversed to a round phenotype after E-30 infection. Further characterization of migrating Th1 effector cells revealed a downregulation of surface adhesion proteins such as LFA-1 PSGL-1, CD44, and CD49d.

Conclusion

Taken together these results suggest that naive CD8⁺ and Th1 effector cells are highly efficient to migrate through the BCSFB in an inflammatory environment. The T cell phenotype is modified during the migration process through HIBCPP cells.

Early childhood infections and the use of antibiotics and antipyretic-analgesics in Finland, Estonia and Russian Karelia

AIM

Infections in early childhood are common reasons to seek medical attention. This study compares the prevalence of infections, and the use of antibiotics and antipyretic-analgesics, in children from Finland, Estonia and Russian Karelia.

METHODS

Children with a genetically increased risk for type 1 diabetes (N = 797) were observed from birth up to 3 years of age. Illnesses and medications were reported by parents continuously. All reported infections, antibiotics and antipyretic-analgesics were compared between Finland and Estonia, and to a lesser extent with Russian Karelia, due to poor study compliance.

RESULTS

Compared with Estonians, Finns reported more infections during the first and second years of life. During the follow-up, Finnish children had 10 infections while Estonians only had 8 (p < 0.001). Finns also used more antibiotics and antipyretic-analgesics in each year during the follow-up. Russian Karelians reported the lowest frequency of infections and the most infrequent use of antibiotics and antipyretic-analgesics in the first two years of life.

CONCLUSION

Infections and the use of antibiotics and antipyretic-analgesics in early childhood were most frequent in Finland, where socio-economic conditions are the most developed and microbial encounters are sparse. This may reflect on the hygiene hypothesis, a less effective immune system that allows normally harmless microbes to attack and cause clinical infections.

Characteristics of familial type 1 diabetes: effects of the relationship to the affected family member on phenotype and genotype at diagnosis

AIMS/HYPOTHESIS

In previous studies, the risk of developing familial type 1 diabetes has been reported to be more than two times higher in the offspring of affected fathers than in those of affected mothers. We tested the hypothesis that index children with an affected father may have a more aggressive disease process at diagnosis than those with other affected first-degree relatives.

METHODS

A cross-sectional, observational study was performed using the Finnish Pediatric Diabetes Register. Clinical and metabolic characteristics, beta cell autoantibodies and HLA class II genetics were analysed from index children in Finland diagnosed before the age of 15 years between January 2003 and December 2016. Information on the presence of type 1 diabetes in first-degree relatives was collected at diagnosis using a structured questionnaire.

RESULTS

Out of 4993 newly diagnosed index children, 519 (10.4%) had familial type 1 diabetes. More than 5% (n = 253, 5.1%) had an affected father, 2.8% (n = 141) had an affected mother, 1.9% (n = 95) had an affected sibling and 0.6% (n = 30) had two or more affected family members. All clinical and metabolic variables were markedly poorer in children with sporadic vs familial diabetes. The index children with an affected father or mother were younger than those with an affected sibling (median age 7.59 vs 6.74 vs 10.73 years, respectively; p < 0.001). After age- and sex-adjusted analyses, index children with an affected father presented more often with ketoacidosis (9.7% vs 3.6%; p = 0.033) and had greater weight loss before diagnosis (3.2% vs 0%; p = 0.006) than those with an affected mother. Children with familial disease tested negative for all autoantibodies more often (3.5% vs 2.1%; p = 0.041) and had insulin autoantibodies more frequently (49.8% vs 42.2%; p = 0.004) than those with sporadic disease. Both major HLA risk haplotypes (DR3-DQ2 and DR4-DQ8) were more often lacking among children with sporadic vs familial disease (15.9% vs 11.2%; p = 0.006). The DR4-DQ8 haplotype was more frequent in the familial vs the sporadic group (75.7% vs 68.5%; p = 0.001) and especially among children with an affected father when compared with children with sporadic disease (77.5% vs 68.5%; p < 0.05). When comparing index children with affected parents diagnosed before or after the birth of the index child, a clear male preponderance was seen among the affected parents diagnosed before the birth of the index child (fathers 66.2% vs mothers 33.8%; p = 0.006), whereas the proportion of fathers and mothers was similar if type 1 diabetes was diagnosed after the birth of the index child.

CONCLUSIONS/INTERPRETATION

The more severe metabolic derangement at diagnosis in children with sporadic type 1 diabetes compared with those with familial type 1 diabetes was confirmed. The higher frequency of diabetic ketoacidosis and increased weight loss at diagnosis in index children with an affected father compared with an affected mother support the hypothesis that paternal type 1 diabetes is associated with more severe disease in the offspring than maternal diabetes. The sex difference seen between affected parents diagnosed before and after the birth of the index child supports the hypothesis that maternal insulin treatment protects against type 1 diabetes.

The heterogeneous pathogenesis of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) results from the destruction of pancreatic β-cells that is mediated by the immune system. Multiple genetic and environmental factors found in variable combinations in individual patients are involved in the development of T1DM. Genetic risk is defined by the presence of particular allele combinations, which in the major susceptibility locus (the HLA region) affect T cell recognition and tolerance to foreign and autologous molecules. Multiple other loci also regulate and affect features of specific immune responses and modify the vulnerability of β-cells to inflammatory mediators. Compared with the genetic factors, environmental factors that affect the development of T1DM are less well characterized but contact with particular microorganisms is emerging as an important factor. Certain infections might affect immune regulation, and the role of commensal microorganisms, such as the gut microbiota, are important in the education of the developing immune system. Some evidence also suggests that nutritional factors are important. Multiple islet-specific autoantibodies are found in the circulation from a few weeks to up to 20 years before the onset of clinical disease and this prediabetic phase provides a potential opportunity to manipulate the islet-specific immune response to prevent or postpone β-cell loss. The latest developments in understanding the heterogeneity of T1DM and characterization of major disease subtypes might help in the development of preventive treatments.

Characteristics of Slow Progression to Type 1 Diabetes in Children With Increased HLA-Conferred Disease Risk

CONTEXT

Characterization of slow progression to type 1 diabetes (T1D) may reveal novel means for prevention of T1D. Slow progressors might carry natural immunomodulators that delay β-cell destruction and mediate preservation of β-cell function.

OBJECTIVE

To identify demographic, genetic, and immunological characteristics of slow progression from seroconversion to clinical T1D.

DESIGN

HLA-susceptible children (n = 7410) were observed from birth for islet cell antibody (ICA), insulin autoantibody (IAA), glutamic acid decarboxylase (GADA), and islet antigen-2 autoantibodies (IA-2A), and for clinical T1D. Disease progression that lasted ≥7.26 years (slowest) quartile from initial seroconversion to diagnosis was considered slow. Autoantibody and genetic characteristics including 45 non-HLA single nucleotide polymorphisms (SNPs) predisposing to T1D were analyzed.

RESULTS

By the end of 2015, 1528 children (21%) had tested autoantibody positive and 247 (16%) had progressed to T1D. The median delay from seroconversion to diagnosis was 8.7 years in slow (n = 62, 25%) and 3.0 years in other progressors. Compared with other progressors, slow progressors were less often multipositive, had lower ICA and IAA titers, and lower frequency of IA-2A at seroconversion. Slow progressors were born more frequently in the fall, whereas other progressors were born more often in the spring. Compared with multipositive nonprogressors, slow progressors were younger, had higher ICA titers, and higher frequency of IAA and multiple autoantibodies at seroconversion. We found no differences in the distributions of non-HLA SNPs between progressors.

CONCLUSIONS

We observed differences in autoantibody characteristics and the season of birth among progressors, but no characteristics present at seroconversion that were specifically predictive for slow progression.

Maturation of Gut Microbiota and Circulating Regulatory T Cells and Development of IgE Sensitization in Early Life

Recent studies suggest that the cross-talk between the gut microbiota and human immune system during the first year of life is an important regulator of the later development of atopic diseases. We explored the changes in the gut microbiota, blood regulatory T cells, and atopic sensitization in a birth-cohort of Estonian and Finnish children followed from 3 to 36 months of age. We describe here an infant Treg phenotype characterized by high Treg frequency, the maturation of Treg population characterized by a decrease in their frequency accompanied with an increase in the highly activated Treg cells. These changes in Treg population associated first with the relative abundance of Bifidobacterium longum followed by increasing colonization with butyrate producing bacteria. High bifidobacterial abundance in the neonatal microbiota appeared to be protective, while colonization with Bacteroides and E. coli was associated with later risk of allergy. Estonian children with lower risk of IgE mediated allergic diseases than Finnish children showed an earlier maturation of the gut microbiota, detected as earlier switch to an increasing abundance of butyrate-producing bacteria, combined with an earlier maturation of Treg cell phenotype and total IgE production. The children with established allergic diseases by age 3 showed a decreased abundance of butyrate producing Faecalibacterium. These results suggest that as well as the maintenance of a bifidobacterial dominated gut microbiota is important during the first weeks of life, the overtake by butyrate producing bacteria seems to be a beneficial shift, which should not be postponed.

Age at Seroconversion, HLA Genotype, and Specificity of Autoantibodies in Progression of Islet Autoimmunity in Childhood

CONTEXT

Children with initial autoantibodies to either insulin (IAA) or glutamic acid decarboxylase (GADA) differ in peak age of seroconversion and have different type 1 diabetes (T1D) risk gene associations, suggesting heterogeneity in the disease process.

OBJECTIVE

To compare the associations of age at seroconversion, HLA risk, and specificity of secondary autoantibodies with the progression of islet autoimmunity between children with either IAA or GADA as their first autoantibody.

DESIGN AND METHODS

A cohort of 15,253 children with HLA-associated increased risk of T1D participated in a follow-up program in which islet autoantibodies were regularly measured. The median follow-up time was 6.7 years. Spearman correlation, Kaplan-Meier survival plots, and Cox proportional-hazard models were used for statistical analyses.

RESULTS

Persistent positivity for at least one of the tested autoantibodies was detected in 998 children; 388 of children progressed to clinical T1D. Young age at initial seroconversion was associated with a high probability of expansion of IAA-initiated autoimmunity and progression to clinical diabetes, whereas expansion of GADA-initiated autoimmunity and progression to diabetes were not dependent on initial seroconversion age. The strength of HLA risk affected the progression of both IAA- and GADA-initiated autoimmunity. The simultaneous appearance of two other autoantibodies increased the rate of progression to diabetes compared with that of a single secondary autoantibody among subjects with GADA-initiated autoimmunity but not among those with IAA as the first autoantibody.

CONCLUSIONS

Findings emphasize the differences in the course of islet autoimmunity initiated by either IAA or GADA supporting heterogeneity in the pathogenic process.

Association of Cereal, Gluten, and Dietary Fiber Intake With Islet Autoimmunity and Type 1 Diabetes

IMPORTANCE

Dietary proteins, such as gluten, have been suggested as triggers of the disease process in type 1 diabetes (T1D).

OBJECTIVE

To study the associations of cereal, gluten, and dietary fiber intake with the development of islet autoimmunity (IA) and T1D.

DESIGN, SETTING, AND PARTICIPANTS

The prospective birth cohort Finnish Type 1 Diabetes Prediction and Prevention Study recruited children with genetic susceptibility to type 1 diabetes from September 1996 to September 2004 from 2 university hospitals in Finland and followed up every 3 to 12 months up to 6 years for diet, islet autoantibodies, and T1D. Altogether 6081 infants (78% of those invited) participated in the study. Dietary data were available for 5714 children (94.0%) and dietary and IA data were available for 5545 children (91.2%), of whom 3762 (68%) had data on islet autoantibodies up to age 6 years. Information on T1D was available for all children. Data were analyzed in 2018 and end point data were updated in 2015.

EXPOSURES

Each child's intake of cereals, gluten, and dietary fiber was calculated from repeated 3-day food records up to 6 years.

MAIN OUTCOMES AND MEASURES

Islet autoimmunity was defined as repeated positivity for islet cell antibodies and at least 1 biochemical autoantibody of 3 analyzed, or T1D. Data on the diagnosis of T1D were obtained from Finnish Pediatric Diabetes Register.

RESULTS

Of 5545 children (2950 boys [53.2%]), 246 (4.4%) developed IA and of 5714 children (3033 boys [53.1%]), 90 (1.6%) developed T1D during the 6-year follow-up. Based on joint models, the intake of oats (hazard ratio [HR], 1.08; 95% CI, 1.03-1.13), wheat (HR, 1.09; 95% CI, 1.03-1.15), rye (HR, 1.13; 95% CI, 1.03-1.23), gluten-containing cereals (HR, 1.07; 95% CI, 1.03-1.11), gluten without avenin from oats (HR, 2.23; 95% CI, 1.40-3.57), gluten with avenin (HR, 2.06; 95% CI, 1.45-2.92), and dietary fiber (HR, 1.41; 95% CI, 1.10-1.81) was associated with the risk of developing IA (HRs for 1 g/MJ increase in intake). The intake of oats (HR, 1.10; 95% CI, 1.00-1.21) and rye (HR, 1.20; 95% CI, 1.03-1.41) was associated with the risk of developing T1D. After multiple testing correction, the associations with IA remained statistically significant.

CONCLUSIONS AND RELEVANCE

A high intake of oats, gluten-containing cereals, gluten, and dietary fiber was associated with an increased risk of IA. Further studies are needed to confirm or rule out the findings and study potential mechanisms.

Early-life exposure to common virus infections did not differ between coeliac disease patients and controls

AIM

Our aim was to compare the presence of various common viruses (rhinovirus, enterovirus, adenovirus, Epstein-Barr virus, cytomegalovirus, norovirus, parechovirus) in stool and nasal swab samples as well as virus-specific antibodies in serum samples between children who developed coeliac disease and controls.

METHODS

A case-control study was established based on the DIABIMMUNE Study cohorts. During the study, eight Estonian children and 21 Finnish children aged 1.5 years to five years developed coeliac disease and each was matched with a disease-free control. Nasal swabs and stool samples were taken at the age of three to six months and the serum samples at the time of diagnosis.

RESULTS

Rhinovirus ribonucleic acid was detected in the nasal swabs from five coeliac disease children, but none of the control children (p = 0.05). There were no statistically significant differences in the level of viral antibodies between cases and controls. Enterovirus immunoglobulin G class antibodies were found more frequently in the Estonian than in the Finnish children (63% versus 23%, p = 0.02).

CONCLUSION

This study did not find any marked overall differences in laboratory-confirmed common viral infections between the children who developed coeliac disease and the controls. However, rhinovirus infections were detected slightly more often in those patients who developed coeliac disease.

Circulating CXCR5-PD-1hi peripheral T helper cells are associated with progression to type 1 diabetes

AIMS/HYPOTHESIS

Type 1 diabetes is preceded by a period of asymptomatic autoimmunity characterised by positivity for islet autoantibodies. Therefore, T helper cell responses that induce B cell activation are likely to play a critical role in the disease process. Here, we aimed to evaluate the role of a recently described subset, C-X-C motif chemokine receptor type 5-negative, programmed cell death protein 1-positive (CXCR5^-PD-1^hi) peripheral T helper (Tph) cells, in human type 1 diabetes.

METHODS

The phenotype of blood CXCR5^-PD-1^hi CD4⁺ T cells was analysed by multicolour flow cytometry. The frequencies of circulating CXCR5^-PD-1^hi T cells were analysed in a cohort of 44 children with newly diagnosed type 1 diabetes, 40 autoantibody-positive (AAb⁺) at-risk children and 84 autoantibody-negative healthy control children, and the findings were replicated in a separate cohort of 15 children with newly diagnosed type 1 diabetes and 15 healthy control children.

RESULTS

Circulating CXCR5^-PD-1^hi Tph cells share several features associated with B cell helper function with circulating CXCR5⁺PD-1^hi follicular T helper (Tfh) cells. Moreover, the frequency of circulating Tph cells was increased in children with newly diagnosed type 1 diabetes, especially in those who are positive for multiple autoantibodies. Importantly, circulating Tph cells were also increased in autoantibody-positive at-risk children who later progressed to type 1 diabetes.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that circulating CXCR5^-PD-1^hi Tph cells are associated with progression to clinical type 1 diabetes. Consequently, Tph cells could have potential both as a biomarker of disease progression and as a target for immunotherapy in type 1 diabetes.

Genetic risk for autoimmunity is associated with distinct changes in the human gut microbiome

Susceptibility to many human autoimmune diseases is under strong genetic control by class II human leukocyte antigen (HLA) allele combinations. These genes remain by far the greatest risk factors in the development of type 1 diabetes and celiac disease. Despite this, little is known about HLA influences on the composition of the human gut microbiome, a potential source of environmental influence on disease. Here, using a general population cohort from the All Babies in Southeast Sweden study, we report that genetic risk for developing type 1 diabetes autoimmunity is associated with distinct changes in the gut microbiome. Both the core microbiome and beta diversity differ with HLA risk group and genotype. In addition, protective HLA haplotypes are associated with bacterial genera Intestinibacter and Romboutsia. Thus, general population cohorts are valuable in identifying potential environmental triggers or protective factors for autoimmune diseases that may otherwise be masked by strong genetic control.

HLA alleles and microbiome alterations have been separately associated with human autoimmunity. Here the authors identify differences in stool microbiome between healthy carriers of HLA alleles conferring low- and high-risk for type 1 diabetes, suggesting that HLA shaping of microbiome may contribute to HLA impact on autoimmunity risks.

Predicting Islet Cell Autoimmunity and Type 1 Diabetes: An 8-Year TEDDY Study Progress Report

OBJECTIVE

Assessment of the predictive power of The Environmental Determinants of Diabetes in the Young (TEDDY)-identified risk factors for islet autoimmunity (IA), the type of autoantibody appearing first, and type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

A total of 7,777 children were followed from birth to a median of 9.1 years of age for the development of islet autoantibodies and progression to T1D. Time-dependent sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated to provide estimates of their individual and collective ability to predict IA and T1D.

RESULTS

HLA genotype (DR3/4 vs. others) was the best predictor for IA (Youden's index J = 0.117) and single nucleotide polymorphism rs2476601, in PTPN22, was the best predictor for insulin autoantibodies (IAA) appearing first (IAA-first) (J = 0.123). For GAD autoantibodies (GADA)-first, weight at 1 year was the best predictor (J = 0.114). In a multivariate model, the area under the ROC curve (AUC) was 0.678 (95% CI 0.655, 0.701), 0.707 (95% CI 0.676, 0.739), and 0.686 (95% CI 0.651, 0.722) for IA, IAA-first, and GADA-first, respectively, at 6 years. The AUC of the prediction model for T1D at 3 years after the appearance of multiple autoantibodies reached 0.706 (95% CI 0.649, 0.762).

CONCLUSIONS

Prediction modeling statistics are valuable tools, when applied in a time-until-event setting, to evaluate the ability of risk factors to discriminate between those who will and those who will not get disease. Although significantly associated with IA and T1D, the TEDDY risk factors individually contribute little to prediction. However, in combination, these factors increased IA and T1D prediction substantially.

Serum 25-Hydroxyvitamin D Concentrations at Birth in Children Screened for HLA-DQB1 Conferred Risk for Type 1 Diabetes

CONTEXT

Vitamin D has several effects on the immune system that might be of relevance for the pathogenesis of type 1 diabetes (T1D).

OBJECTIVE

To evaluate whether umbilical cord serum concentrations of 25-hydroxy-vitamin D (25[OH]D) differ in children developing either islet autoimmunity (IA) or overt T1D during childhood and adolescence.

DESIGN

Umbilical cord serum samples from 764 children born from 1994 to 2004 with HLA-DQB1 conferred risk for T1D participating in the Type 1 Diabetes Prediction and Prevention Study were analyzed for 25(OH)D using an enzyme immunoassay.

SETTING

DIPP clinics in Turku, Oulu, and Tampere University Hospitals, Finland.

PARTICIPANTS

Two hundred fifty children who developed T1D diabetes at a median age of 6.7 years (interquartile range [IQR] 4.0 to 10.1 years) and 132 additional case children who developed IA, i.e., positivity for multiple islet autoantibodies. Cases were matched for date of birth, gender, and area of birth with 382 control children who remained autoantibody negative. The median duration of follow up was 9.8 years (IQR 5.7 to 13.1 years).

MAIN OUTCOME MEASURE

The median 25(OH)D concentrations.

RESULTS

The median 25(OH)D concentration in cord serum was low [31.1 nmol/L (IQR 24.0 to 41.8); 88% <50 nmol/L], but not statistically different between children who developed T1D or IA and their control groups (P = 0.70). The levels were associated mainly with geographical location, year and month of birth, age of the mother, and maternal intake of vitamin D during pregnancy.

CONCLUSIONS

The 25(OH)D concentrations at birth are not associated with the development of T1D during childhood.

Gliptin-associated Bullous Pemphigoid and the Expression of Dipeptidyl Peptidase-4/CD26 in Bullous Pemphigoid

Dipeptidyl peptidase-4 inhibitors (DPP-4i or gliptins) increase the risk of developing bullous pemphigoid (BP). To clarify, whether gliptin-associated BP has special features, we analyzed the clinical, histopathological and immunological features of 27 BP patients, 10 of which previously used gliptin medication. Compared to those who had not previously received gliptins, subjects who had, showed higher BP180-NC16A ELISA (enzyme-linked immunosorbent assay) values, fewer neurological co-morbidities and shorter time to remission, but differences were not statistically significant. The HLA-DQB1*03:01 allele was more commonly present among the BP patients than the control population, but was not more common in those with gliptin history. To determine the effect of gliptins on the expression of the DPP-4/CD-26 protein we performed immunohistochemistry, which showed that the skin expression of DPP-4/CD-26 was increased in BP patients, but not affected by prior gliptin treatment. We conclude that DPP-4i medication is common among BP patients and prior gliptin treatment may be associated with some specific features.

Rhinoviruses in infancy and risk of immunoglobulin E sensitization

Previous data about the role of viruses in the development of allergic immunoglobulin E (IgE) sensitization are contradictory. The aim of this study was to determine the possible associations between exposure to different viruses (rhinovirus, enterovirus, norovirus, and parechovirus) during the first year of life and IgE sensitization. Viruses were analyzed from stool samples collected monthly from infants participating in a prospective birth cohort study. From that study, 244 IgE sensitized case children and 244 nonsensitized control children were identified based on their allergen-specific IgE antibody levels at the age of 6, 18, and 36 months. Stool samples (n = 4576) from the case and control children were screened for the presence of rhinovirus, enterovirus, norovirus, and parechovirus RNA by reverse transcription quantitative polymerase chain reaction. The study showed that rhinovirus was the most prevalent virus detected, present in 921 (20%) samples. None of the viruses were associated with IgE sensitization in the full cohort but after stratifying by sex, the number of rhinovirus positive samples was inversely associated with IgE sensitization in boys (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.69-0.94; P = 0.006). There was also a temporal relation between rhinoviruses and IgE sensitization, as rhinovirus exposure during the first 6 months of life was associated with a reduced risk of subsequent IgE sensitization in boys (OR: 0.76; 95% CI: 0.6-0.94; P = 0.016). In conclusion, early exposure to rhinoviruses was inversely associated with IgE sensitization but this protective association was restricted to boys.

Early childhood CMV infection may decelerate the progression to clinical type 1 diabetes

AIMS/HYPOTHESIS

Evidence of the role of cytomegalovirus (CMV) infection in the pathogenesis of type 1 diabetes (T1D) has remained inconclusive. Our aim was to elucidate the possible role of CMV infection in the initiation of islet autoimmunity and in the progression to clinical T1D among children with human leukocyte antigen (HLA)-conferred T1D risk.

METHODS

A total of 1402 children from the prospective Type 1 Diabetes Prediction and Prevention (DIPP) study were analyzed for CMV-specific IgG antibodies during early childhood. All the children carried HLA-DQ genotypes associated with increased risk for T1D. The effect of CMV infection on the appearance of T1D-associated autoantibodies (insulin autoantibodies [IAA], glutamic acid decarboxylase [GADA], and insulinoma antigen-2 [IA-2A], n = 356) and on the progression rate to clinical T1D (n = 233) were analyzed with Kaplan-Meier survival analysis and Log-rank test.

RESULTS

Early childhood CMV infection was inversely associated with the development of T1D during childhood. Cumulative progression to T1D was decreased in subjects with an early CMV infection (P = 0.035). In further analyses, the effect of early CMV infection on the initiation of islet autoimmunity and progression to clinical T1D were examined separately. Interestingly, early CMV infection did not affect the appearance of T1D-associated autoantibodies but a decelerating effect was observed on the progression rate from islet autoimmunity to clinical T1D (P = 0.015).

CONCLUSION

Our results suggest that an early childhood CMV infection may decelerate the progression from islet autoimmunity to clinical T1D among at-risk children and may thus protect these children from progressing to T1D during childhood.

FOXP3+ Regulatory T Cell Compartment Is Altered in Children With Newly Diagnosed Type 1 Diabetes but Not in Autoantibody-Positive at-Risk Children

The dysfunction of FOXP3-positive regulatory T cells (Tregs) plays a key role in the pathogenesis of autoimmune diseases, including type 1 diabetes (T1D). However, previous studies analyzing the peripheral blood Treg compartment in patients with T1D have yielded partially conflicting results. Moreover, the phenotypic complexity of peripheral blood Tregs during the development of human T1D has not been comprehensively analyzed. Here, we used multi-color flow cytometry to analyze the frequency of distinct Treg subsets in blood samples from a large cohort comprising of 74 children with newly diagnosed T1D, 76 autoantibody-positive children at-risk for T1D and 180 age- and HLA-matched control children. The frequency of CD4+CD25+CD127lowFOXP3+ Tregs was higher in children with T1D compared to control children, and this change was attributable to a higher proportion of naïve Tregs in these subjects. Further longitudinal analyses demonstrated that the increase in Treg frequency correlated with disease onset. The frequencies of the minor subsets of CD25+FOXP3low memory Tregs as well as CD25lowCD127lowFOXP3+ Tregs were also increased in children with T1D. Moreover, the ratio of CCR6-CXCR3+ and CCR6+CXCR3- memory Tregs was altered and the frequency of proliferating Ki67-positive and IFN-γ producing memory Tregs was decreased in children with T1D. The frequency of CXCR5+FOXP3+ circulating follicular T regulatory cells was not altered in children with T1D. Importantly, none of the alterations observed in children with T1D were observed in autoantibody-positive at-risk children. In conclusion, our study reveals multiple alterations in the peripheral blood Treg compartment at the diagnosis of T1D that appear not to be features of early islet autoimmunity.

No evidence of the role of early chemical exposure in the development of β-cell autoimmunity

Exposure to environmental chemicals can modulate the developing immune system, but its role in the pathogenesis of type 1 diabetes is largely unexplored. Our objective was to study the levels of circulating concentrations of environmental pollutants during the first years of life and their associations with the later risk of diabetes-predictive autoantibodies. From two birth-cohort studies including newborn infants with HLA-conferred susceptibility to type 1 diabetes (FINDIA and DIABIMMUNE), we identified case children with at least one biochemical diabetes-associated autoantibody (n = 30-40) and from one to four autoantibody-negative controls per each case child matched for age, gender, diabetes-related HLA-risk, delivery hospital, and, in FINDIA, also dietary intervention group. Plasma levels of 13 persistent organic pollutants and 14 per- and polyfluorinated substances were analyzed in cord blood and plasma samples taken at the age of 12 and 48 months. Both breastfeeding and the geographical living environment showed association with circulating concentrations of some of the chemicals. Breastfeeding-adjusted conditional logistic regression model showed association between decreased plasma HBC concentration at 12-month-old children and the appearance of diabetes-associated autoantibodies (HR, 0.989; 95% Cl, 0.978-1.000; P = 0.048). No association was found between the plasma chemical levels and the development of clinical type 1 diabetes. Our results do not support the view that exposure to the studied environmental chemicals during fetal life or early childhood is a significant risk factor for later development of β-cell autoimmunity and type 1 diabetes.