The development of immune responses and gut microbiota in children at genetic risk of type 1 diabetes

The incidence of type 1 diabetes (T1D) has rapidly increased in the Western world and the age of onset has shifted to younger ages. T1D is an autoimmune disease that results from the destruction of insulin-producing pancreatic β-cells caused by attack from the body s own immune system. The exact disease pathogenesis is unknown, but genetic and environmental factors have a significant effect on the development of the disease. The aim of this study was to determine how the immune system develops in children with a T1D associated genetic risk. The differentiation of cord blood T cells cultured in type 1 and type 2 cytokine environments was investigated between infants with a diabetes-associated HLA risk genotype and infants without a risk genotype. In infants with a diabetes-associated HLA risk genotype, the expression of transcription factor GATA-3 and chemokine receptor CCR4 was reduced in T cells differentiated in a type 2 cytokine environment. Thus, infants with a T1D-associated risk genotype may develop an aberrant immune response to environmental factors. Previous epidemiological studies have demonstrated a reduced risk of T1D in the offspring of mothers with T1D when compared with children of affected fathers. We examined whether exposure of offspring to maternal insulin therapy in utero induces insulin-specific regulatory mechanisms. In cord blood the expression of transcription factor FOXP3 in CD4+CD25+ regulatory T cells was higher in the offspring of mothers with T1D than in infants of unaffected mothers. After in vitro insulin stimulation, the expression of FOXP3 in regulatory CD4+CD25+ T cells, and up-regulation of immunological response related genes (FOXP3, IL-10, TGF-β, NFATc2 and STIM1) was only increased in the offspring of mothers with T1D. The results suggest that maternal insulin therapy specifically increases regulatory T cell activation and the development of tolerance to insulin in the fetus. This may explain the lower risk of diabetes in children with maternal vs. paternal diabetes. The factors reflecting oral tolerance were evaluated, such as the early development of antibodies to cow s milk proteins in children who later developed T1D, and the gut microbiota in relation to β-cell autoimmunity was studied. The results indicate that children who progress to diabetes have a stronger antibody response to cow s milk proteins during the first year of life than children without signs of β-cell autoimmunity. The results may suggest an early dysregulation of oral tolerance in children who later progress to T1D. We investigated the composition of the intestinal microbiota in fecal samples from children with T1D-related autoantibodies and from autoantibody-negative children. An increased abundance of the genus Bacteroides and low abundances of Bifidobacteria and butyrate-producing species were found in the children with T1D-related autoantibodies. The results suggest that there are several indications that abnormalities in the intestinal immune system, such as an enhanced immune response to dietary protein as well as imbalanced gut microbiota, are associated with the development of T1D.Tyypin 1 diabeteksen (T1D) ilmaantuvuus on nopeasti kasvanut länsimaissa ja tautiin sairastutaan nuorempana. T1D on autoimmuunisairaus, joka syntyy haiman insuliinia tuottavien β-solujen tuhouduttua elimistön oman immuunipuolustusjärjestelmän hyökkäyksen seurauksena. Taudin tarkkaa syntymekanismia ei tiedetä, mutta perimällä ja ympäristötekijöillä on merkittävä vaikutus taudin kehittymiseen. Tutkimuksen tarkoituksena oli selvittää, miten immuunijärjestelmä kehittyy lapsilla, joilla on T1D:een liittyvä riskiperimä. Napaveren T-solujen erilaistuminen ns. tyypin 1 ja tyypin 2 sytokiiniympäristössä tutkittiin lapsilla, joilla on diabetekseen liittyvä HLA-riskiperimä verrattuna lapsiin, joilla ei ole tällaista riskiperimää. T-solujen erilaistuminen tyypin 2 sytokiiniympäristössä poikkesi ns. riskilapsilla siten, että GATA-3 transkriptiofaktorin ja CCR4 kemokiinireseptorin ilmentyminen jäi alhaiseksi. T1D:n riskiperimän omaavan lapsen immuunivaste ympäristötekijöitä kohtaan voi olla näin ollen poikkeava. Aikaisempien epidemiologisten tutkimusten perusteella on havaittu, että lapsilla, joiden äidillä on diabetes, on alhaisempi riski sairastua diabetekseen kuin diabetesta sairastavien isien lapsilla. Tutkimuksessa selvitettiin, miten sikiöaikainen äidin insuliinihoito vaikuttaa lapsen insuliinispesifisen immuunivasteen säätelyyn. Napaveressä transkriptiotekijä FOXP3:n ilmentyminen regulatorisissa CD4+CD25+ T-soluissa oli suurempi vastasyntyneillä lapsilla, joiden äidillä oli T1D verrattuna lapsiin, joiden äidillä ei ollut diabetesta. Lisäksi insuliinistimulaation jälkeen havaittiin diabeetikon lapsen lymfosyyteissä enemmän transkriptiotekijä FOXP3:n ilmenemistä CD4+CD25+ soluissa ja immunivasteen aktivaatioon liittyvien geenien (FOXP3, IL-10, TGF-β, NFATc2 ja STIM1) esiintymistä. Tulokset viittaavat siihen, että äidin insuliinihoito lisää regulatoristen T-solujen aktivaatiota spesifisesti ja lapselle kehittyy toleranssi insuliinia kohtaan jo sikiökaudella. Tämä voi selittää sen, että jos äidillä on diabetes, lapsen riski sairastua diabetekseen on pienempi kuin jos esim. isällä on diabetes. Oraaliseen toleranssiin vaikuttavia tekijöitä tutkittiin, kuten varhaista vasta-aineiden kehittymistä lehmänmaidon proteiineja kohtaan lapsilla, jotka sairastuivat diabetekseen ja lisäksi tutkittiin suoliston mikrobifloora suhteessa β-solu autoimmuniteettiin. Tulokset osoittavat, että lapsilla, jotka sairastuvat myöhemmin diabetekseen, on poikkeavan voimakas vasta-ainemuodostus ensimmäisen elinvuoden aikana lehmänmaidon proteiineja kohtaan verrattuna autovasta-aine negatiivisiin lapsiin. Tulokset viittaavat oraalisen toleranssin häiriöön diabetekseen sairastuvilla lapsilla ennen varsinaista taudin puhkeamista. Olemme tutkineet suoliston mikrobiflooran koostumusta ulostenäytteistä lapsilla, joille on ilmaantunut T1D:een liittyviä autovasta-aineita sekä lapsilla, joilla ei ole autovasta-aineita. Tutkimuksen perusteella Bacteroides-lajia esiintyy enemmän autovasta-aine positiivisilla lapsilla, kun taas tiettyjen Bifidobakteerien sekä voihappoa tuottavien bakteerikantojen määrä on alhaisempi. Tulokset viittaavat siihen, että suoliston puolustusjärjestelmän poikkeavuudet, kuten voimakas varhainen immuunivaste ravinnon proteiineja kohtaan sekä suoliston mikrobiston epätasapaino, liittyvät T1D:n kehittymiseen

HUS Lasten kotisairaalan erityispiirteitä

Teema : palliatiivinen hoit

Increased HLA class II risk is associated with a more aggressive presentation of clinical type 1 diabetes

Peer reviewe

Increased HLA class II risk is associated with a more aggressive presentation of clinical type 1 diabetes

Aim: To determine the association of HLA class II risk with the demographic and clinical characteristics of type 1 diabetes at diagnosis. Methods: We conducted a register-based retrospective cohort study of 4993 Finnish children (2169 girls) – diagnosed with type 1 diabetes under the age of 15 years in 2003–2016. The participants were divided into six risk groups based on their HLA DR/DQ genotype. Demographic characteristics, family history of type 1 diabetes and metabolic markers at the time of diagnosis were compared between the groups. Results: In total, 4056/4993 children (81.2%) carried an HLA genotype associated with an increased risk of type 1 diabetes (risk groups 3–5), whereas 937/4993 children (18.8%) carried a HLA genotype conferring no or decreased disease risk. Children with higher HLA risk were younger at diagnosis (p < 0.001) and had a shorter duration of classical symptoms before diagnosis (p = 0.016). Subjects in the high-risk group were more likely to have a family member affected by type 1 diabetes when compared to those in the neutral risk group (11.5% vs. 8.8%, p = 0.05). Conclusion: Children with stronger HLA disease susceptibility are younger at their disease manifestation and have a shorter period of symptoms before diagnosis, suggesting that the HLA class II genes are associated with a more aggressive disease presentation.publishedVersionPeer reviewe

Higher circulating EGF levels associate with a decreased risk of IgE sensitization in young children

Background Decreased exposure to microbial agents in industrialized countries and urban living areas is considered as a risk factor of developing immune-mediated diseases, such as allergies and asthma. Epithelial surfaces in the gastrointestinal and respiratory tracts and in the skin constitute the primary areas in contact with the environmental microbial load. Methods We analyzed the levels of 30 cytokines and growth factors in serum or plasma as markers of the immune maturation in the participants in the DIABIMMUNE study from Russian Karelia (n = 60), Estonia (n = 83) and Finland (n = 89), three neighboring countries with remarkable differences in the incidences of allergies, asthma and autoimmune diseases. Results We observed an upregulation of T helper cell signature cytokines during the first 12 months of life, reflecting natural development of adaptive immune responses. During the first years of life, circulating concentrations of epidermal growth factor (EGF) were significantly higher, especially in Russian children compared with Finnish children. The children who developed IgE sensitization showed lower levels of EGF than those without such responses. Conclusion Our results suggest that low circulating EGF levels associate with the risk of allergies possibly via the effects on the epithelial integrity and mucosal homeostasis.Peer reviewe

Higher circulating EGF levels associate with a decreased risk of IgE sensitization in young children

Background Decreased exposure to microbial agents in industrialized countries and urban living areas is considered as a risk factor of developing immune-mediated diseases, such as allergies and asthma. Epithelial surfaces in the gastrointestinal and respiratory tracts and in the skin constitute the primary areas in contact with the environmental microbial load. Methods We analyzed the levels of 30 cytokines and growth factors in serum or plasma as markers of the immune maturation in the participants in the DIABIMMUNE study from Russian Karelia (n = 60), Estonia (n = 83) and Finland (n = 89), three neighboring countries with remarkable differences in the incidences of allergies, asthma and autoimmune diseases. Results We observed an upregulation of T helper cell signature cytokines during the first 12 months of life, reflecting natural development of adaptive immune responses. During the first years of life, circulating concentrations of epidermal growth factor (EGF) were significantly higher, especially in Russian children compared with Finnish children. The children who developed IgE sensitization showed lower levels of EGF than those without such responses. Conclusion Our results suggest that low circulating EGF levels associate with the risk of allergies possibly via the effects on the epithelial integrity and mucosal homeostasis.</p

Early fecal microbiota composition in children who later develop celiac disease and associated autoimmunity

Objectives: Several studies have reported that the intestinal microbiota composition of celiac disease (CD) patients differs from healthy individuals. The possible role of gut microbiota in the pathogenesis of the disease is, however, not known. Here, we aimed to assess the possible differences in early fecal microbiota composition between children that later developed CD and healthy controls matched for age, sex and HLA risk genotype.Materials and methods: We used 16S rRNA gene sequencing to examine the fecal microbiota of 27 children with high genetic risk of developing CD. Nine of these children developed the disease by the age of 4 years. Stool samples were collected at the age of 9 and 12 months, before any of the children had developed CD. The fecal microbiota composition of children who later developed the disease was compared with the microbiota of the children who did not have CD or associated autoantibodies at the age of 4 years. Delivery mode, early nutrition, and use of antibiotics were taken into account in the analyses.Results: No statistically significant differences in the fecal microbiota composition were found between children who later developed CD (n = 9) and the control children without disease or associated autoantibodies (n = 18).Conclusions: Based on our results, the fecal microbiota composition at the age of 9 and 12 months is not associated with the development of CD. Our results, however, do not exclude the possibility of duodenal microbiota changes or a later microbiota-related trigger for the disease.</p

Fungal Dysbiosis and Intestinal Inflammation in Children With Beta-Cell Autoimmunity

Although gut bacterial dysbiosis is recognized as a regulator of beta-cell autoimmunity, no data is available on fungal dysbiosis in the children at the risk of type 1 diabetes (T1D). We hypothesized that the co-occurrence of fungal and bacterial dysbiosis contributes to the intestinal inflammation and autoimmune destruction of insulin-producing beta-cells in T1D. Fecal and blood samples were collected from 26 children tested positive for at least one diabetes-associated autoantibody (IAA, GADA, IA-2A or ICA) and matched autoantibody-negative children with HLA-conferred susceptibility to T1D (matched for HLA-DQB1 haplotype, age, gender and early childhood nutrition). Bacterial 16S and fungal ITS2 sequencing, and analyses of the markers of intestinal inflammation, namely fecal human beta-defensin-2 (HBD2), calprotectin and secretory total IgA, were performed. Anti-Saccharomyces cerevisiae antibodies (ASCA) and circulating cytokines, IFNG, IL-17 and IL-22, were studied. After these analyses, the children were followed for development of clinical T1D (median 8 years and 8 months). Nine autoantibody positive children were diagnosed with T1D, whereas none of the autoantibody negative children developed T1D during the follow-up. Fungal dysbiosis, characterized by high abundance of fecal Saccharomyces and Candida, was found in the progressors, i.e., children with beta-cell autoimmunity who during the follow-up progressed to clinical T1D. These children showed also bacterial dysbiosis, i.e., increased Bacteroidales and Clostridiales ratio, which was, however, found also in the non-progressors, and is thus a common nominator in the children with beta-cell autoimmunity. Furthermore, the progressors showed markers of intestinal inflammation detected as increased levels of fecal HBD2 and ASCA IgG to fungal antigens. We conclude that the fungal and bacterial dysbiosis, and intestinal inflammation are associated with the development of T1D in children with beta-cell autoimmunity

Genomic variation and strain-specific functional adaptation in the human gut microbiome during early life

The human gut microbiome matures towards the adult composition during the first years of life and is implicated in early immune development. Here, we investigate the effects of microbial genomic diversity on gut microbiome development using integrated early childhood data sets collected in the DIABIMMUNE study in Finland, Estonia and Russian Karelia. We show that gut microbial diversity is associated with household location and linear growth of children. Single nucleotide polymorphism- and metagenomic assembly-based strain tracking revealed large and highly dynamic microbial pangenomes, especially in the genus Bacteroides, in which we identified evidence of variability deriving from Bacteroides-targeting bacteriophages. Our analyses revealed functional consequences of strain diversity; only 10% of Finnish infants harboured Bifidobacterium longum subsp. infantis, a subspecies specialized in human milk metabolism, whereas Russian infants commonly maintained a probiotic Bifidobacterium bifidum strain in infancy. Groups of bacteria contributing to diverse, characterized metabolic pathways converged to highly subject-specific configurations over the first two years of life. This longitudinal study extends the current view of early gut microbial community assembly based on strain-level genomic variation.Peer reviewe

Alkaptonurian geenivirhe. Sinisen miehen salaisuus: alkaptonuria.

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