Diagnostic Delay of Celiac Disease in Childhood.

Importance: The extent and factors associated with risk of diagnostic delay in pediatric celiac disease (CD) are poorly understood. Objectives: To investigate the diagnostic delay of CD in childhood, and to assess factors associated with this delay. Design, Setting, and Participants: Multicenter, retrospective, cross-sectional study (2010-2019) of pediatric (aged 0-18 years) patients with CD from 13 pediatric tertiary referral centers in Italy. Data were analyzed from January to June 2023. Main Outcomes and Measures: The overall diagnostic delay (ie, the time lapse occurring from the first symptoms or clinical data indicative of CD and the definitive diagnosis), further split into preconsultation and postconsultation diagnostic delay, were described. Univariable and multivariable linear regression models for factors associated with diagnostic delay were fitted. Factors associated with extreme diagnostic delay (ie, 1.5 × 75th percentile) and misdiagnosis were assessed. Results: A total of 3171 patients with CD were included. The mean (SD) age was 6.2 (3.9) years; 2010 patients (63.4%) were female; and 10 patients (0.3%) were Asian, 41 (1.3%) were Northern African, and 3115 (98.3%) were White. The median (IQR) overall diagnostic delay was 5 (2-11) months, and preconsultation and postconsultation diagnostic delay were 2 (0-6) months and 1 (0-3) month, respectively. The median (IQR) extreme overall diagnostic delay (586 cases [18.5%]) was 11 (5-131) months, and the preconsultation and postconsultation delays were 6 (2-120) and 3 (1-131) months, respectively. Patients who had a first diagnosis when aged less than 3 years (650 patients [20.5%]) showed a shorter diagnostic delay, both overall (median [IQR], 4 [1-7] months for patients aged less than 3 years vs 5 [2-12] months for others) and postconsultation (median [IQR], 1 [0-2] month for patients aged less than 3 years vs 2 [0-4] months for others). A shorter delay was registered in male patients, both overall (median [IQR], 4 [1-10] months for male patients vs 5 [2-12] months for female patients) and preconsultation (median [IQR], 1 [0-6] month for male patients vs 2 [0-6] months for female patients). Family history of CD was associated with lower preconsultation delay (odds ratio [OR], 0.59; 95% CI, 0.47-0.74) and lower overall extreme diagnostic delay (OR, 0.75; 95% CI, 0.56-0.99). Neurological symptoms (78 patients [21.5%]; OR, 1.35; 95% CI, 1.03-1.78), gastroesophageal reflux (9 patients [28.1%]; OR, 1.87; 95% CI, 1.02-3.42), and failure to thrive (215 patients [22.6%]; OR, 1.62; 95% CI, 1.31-2.00) showed a more frequent extreme diagnostic delay. A previous misdiagnosis (124 patients [4.0%]) was more frequently associated with gastroesophageal reflux disease, diarrhea, bloating, abdominal pain, constipation, fatigue, osteopenia, and villous atrophy (Marsh 3 classification). Conclusions and Relevance: In this cross-sectional study of pediatric CD, the diagnostic delay was rather short. Some factors associated with risk for longer diagnostic delay and misdiagnosis emerged, and these should be addressed in future studies.

Novel Bacteroides Vulgatus strain protects against gluten-induced break of human celiac gut epithelial homeostasis: a pre-clinical proof-of-concept study.

BACKGROUND AND AIMS: We have identified a decreased abundance of microbial species known to have a potential anti-inflammatory, protective effect in subjects that developed Celiac Disease (CeD) compared to those who did not. We aim to confirm the potential protective role of one of these species, namely Bacteroides vulgatus, and to mechanistically establish the effect of bacterial bioproducts on gluten-dependent changes on human gut epithelial functions. METHODS: We identified, isolated, cultivated, and sequenced a unique novel strain (20220303-A2) of B. vulgatus found only in control subjects. Using a human gut organoid system developed from pre-celiac patients, we monitored epithelial phenotype and innate immune cytokines at baseline, after exposure to gliadin, or gliadin plus B. vulgatus cell free supernatant (CFS). RESULTS: Following gliadin exposure, we observed increases in epithelial cell death, epithelial monolayer permeability, and secretion of pro-inflammatory cytokines. These effects were mitigated upon exposure to B. vulgatus 20220303-A2 CFS, which had matched phenotype gene product mutations. These protective effects were mediated by epigenetic reprogramming of the organoids treated with B. vulgatus CFS. CONCLUSIONS: We identified a unique strain of B. vulgatus that may exert a beneficial role by protecting CeD epithelium against a gluten-induced break of epithelial tolerance through miRNA reprogramming. IMPACT: Gut dysbiosis precedes the onset of celiac disease in genetically at-risk infants. This dysbiosis is characterized by the loss of protective bacterial strains in those children who will go on to develop celiac disease. The paper reports the mechanism by which one of these protective strains, B. vulgatus, ameliorates the gluten-induced break of gut epithelial homeostasis by epigenetically re-programming the target intestinal epithelium involving pathways controlling permeability, immune response, and cell turnover.

Zonulin as a Biomarker for the Development of Celiac Disease.

OBJECTIVES: Increased intestinal permeability seems to be a key factor in the pathogenesis of autoimmune diseases, including celiac disease (CeD). However, it is unknown whether increased permeability precedes CeD onset. This study's objective was to determine whether intestinal permeability is altered before celiac disease autoimmunity (CDA) in at-risk children. We also examined whether environmental factors impacted zonulin, a widely used marker of gut permeability. METHODS: We evaluated 102 children in the CDGEMM study from 2014-2022. We included 51 CDA cases and matched controls, who were enrolled for 12 months or more and consumed gluten. We measured serum zonulin from age 12 months to time of CDA onset, and the corresponding time point in controls, and examined clinical factors of interest. We ran a mixed-effects longitudinal model with dependent variable zonulin. RESULTS: Children who developed CDA had a significant increase in zonulin in the 18.3 months (range 6-78) preceding CDA compared to those without CDA (slope differential = ß = 0.1277, 95% CI: 0.001, 0.255). Among metadata considered, zonulin trajectory was only influenced by increasing number of antibiotic courses, which increased the slope of trajectory of zonulin over time in CDA subjects (P = .04). CONCLUSIONS: Zonulin levels significantly rise in the months that precede CDA diagnosis. Exposure to a greater number of antibiotic courses was associated with an increase in zonulin levels in CDA subjects. This suggests zonulin may be used as a biomarker for preclinical CeD screening in at-risk children, and multiple antibiotic courses may increase their risk of CDA by increasing zonulin levels.

Investigating the Relationship Between COVID-19 and Celiac Disease. A Dual Research Approach.

Background: Most evidence on the coronavirus disease 2019 (COVID-19) pandemic, has been obtained from web- or telephone-based surveys. In particular, few laboratory data, often incomplete, have been reported on the frequency of COVID-19-related serology at celiac disease (CD) diagnosis or on the effects of COVID-19 on the development of CD-specific autoimmunity. Objectives: The objective of this retrospective cross-sectional case/control study was to: (1) evaluate the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in 78 children and adolescents at CD diagnosis (CD, 44 females, median age 7.4 years); (2) evaluate the frequency of IgA-anti-transglutaminase antibodies (IgA-tTGAbs) in 97 nonceliac patients (50 females, median age 9.0 years) who contracted SARS-CoV-2 infection during the pandemic (February-April 2021). As a control (CTRL) group, we analyzed 141 healthy subjects (79 females, median age 9.8 years) enrolled during the pandemic. Methods: SARS-CoV-2 IgM- and IgG-antibodies were detected by chemiluminescent microparticle immunoassays. IgA-tTGAbs were detected by a fluid-phase radioimmunoassay. Results: Six out of 78 (7.7%) CD patients tested positive for SARS-CoV-2Abs, with a frequency not significantly different from CTRL subjects (9.2%). None of the 97 nonceliac COVID-19 patients tested positive for IgA-tTG antibodies. Conclusion: These 2 distinct research approaches showed (1) similar frequencies of SARS-CoV-2 immunoreactivities in CD patients and CTRL subjects and, (2) no ability of SARS-CoV-2 to induce a CD-specific immune response, at least in the 3-4 months following SARS-CoV-2 infection.

No effects of COVID-19 on the development of type 1 diabetes autoimmunity and no evidence of an increased frequency of SARS-CoV-2 antibodies in newly diagnosed type 1 diabetes patients relative to healthy subjects.

AIMS: To evaluate the relationship between SARS-CoV-2 infection and autoimmunity in type 1 diabetes (T1D) and SARS-CoV-2 antibodies frequency at diagnosis of T1D during pandemic. METHODS: The presence of T1D-specific autoimmunity was evaluated in a cohort of 99 children and adolescents without diabetes that contracted SARS-CoV-2 infection. Moreover, the frequency of IgM- and IgG-SARS-CoV-2 antibodies was evaluated in 41 newly diagnosed T1D patients not yet vaccinated against SARS-CoV-2 disease, collected during the pandemic, compared to healthy subjects (CTRL). RESULTS: None of the 99 patients that contracted SARS-CoV-2 infection during the pandemic period was found positive for T1D autoantibodies. The frequency of SARS-CoV-2 antibodies was not significantly different in patients newly diagnosed with T1D (12.2%), compared with CTRL (8.4%). Among SARS-CoV-2 antibody positive T1D patients, 80% were target of diabetes autoantibodies and 60% had another concomitant autoimmune disease. Among the CTRL subjects positive for SARS-CoV-2Abs (n = 10), none was found positive for T1D autoantibodies. CONCLUSIONS: The results of the present study do not confirm, at least in the short term, a role of COVID-19 as a potential trigger of T1D autoimmunity and do not provide evidence of an increased frequency of SARS-CoV-2 antibodies in newly diagnosed T1D patients in comparison with healthy population.

Role of age in dynamics of autoantibodies in pediatric Celiac disease.

BACKGROUND: Celiac disease (CD) is characterized by elevated serum titers of autoantibodies IgA anti-tissue transglutaminase 2 (TGA-IgA) and IgA anti-endomysial (EMA), with small bowel mucosa atrophy. We evaluated age differences between CD children exhibiting variable antibody titers at diagnosis. METHODS: CD children diagnosed between January 2014 and June 2019, according to 2012 ESPGHAN guidelines were studied. All had EMA and TGA-IgA measurements, while a proportion of them underwent esophagogastroduodenoscopy (EGD). Patients were grouped based on serum TGA-IgA titers normalized to the upper limit of normal (ULN) and differences in median age (years) assessed by analysis of variance (ANOVA) and creation of orthogonal contrasts. RESULTS: CD was diagnosed in 295 subjects (median age: 4.4 [IQR: 2.60-8.52]) with a biopsy sparing protocol (high titer: ≥ 10xULN) and in 204 by EGD biopsy. Of the latter, 142 (median age: 8.5 [IQR: 5.81-11.06]) and 62 (median age: 9.5 [IQR: 6.26-12.76]) had a low (< 5xULN) and a moderate (≥ 5 < 10xULN) TGA-IgA titer, respectively. Potential CD was diagnosed in 20 patients (median age: 3.6 [IQR: 2.47-6.91]). The median age was significantly lower in the no-biopsy group (ANOVA: F(3, 516) = 25.98, p < .001) than in low- and moderate titer groups (p < 0.0001), while there was no statistical difference between biopsy-sparing and potential CD groups. CONCLUSION: CD patients with greatly elevated antibody titers (≥ 10xULN) were diagnosed at an earlier age than those with lower titers. This may indicate that an increase in TGA-IgA is independent of age and suggests a polarization of autoimmunity in younger individuals with higher serum antibody levels.

Early Antibody Dynamics in a Prospective Cohort of Children At Risk of Celiac Disease.

INTRODUCTION: The purpose of this study was to identify possible serum biomarkers predicting celiac disease (CD) onset in children at risk. METHODS: A subgroup from an ongoing, international prospective study of children at risk of CD was classified according to an early trajectory of deamidated gliadin peptides (DGPs) immunoglobulin (Ig) G and clinical outcomes (CD, potential CD, and CD autoimmunity). RESULTS: Thirty-eight of 325 children developed anti-tissue transglutaminase IgA antibody (anti-tTG IgA) seroconversion. Twenty-eight of 38 children (73.6%) showed an increase in anti-DGPs IgG before their first anti-tTG IgA seroconversion. DISCUSSION: Anti-DGPs IgG can represent an early preclinical biomarker predicting CD onset in children at risk.

Prevalence and detection rate of celiac disease in Italy: Results of a SIGENP multicenter screening in school-age children.

BACKGROUND: Celiac disease is a common lifelong disorder. Recent studies indicate that the number of clinically detected cases has increased over the last decades, however little is known about changes in the prevalence and the detection rate of celiac disease. AIM: To evaluate the current prevalence and detection rate of celiac disease in Italy by a multicenter, mass screening study on a large sample of school-age children. METHODS: children aged 5-11 years were screened at school by HLA-DQ2 and -DQ8 determination on a drop of blood in six Italian cities; total serum IgA and IgA anti-transglutaminase were determined in children showing HLA-DQ2 and/or -DQ8 positivity. Diagnosis of celiac disease was confirmed according to the European guidelines. RESULTS: 5994 children were eligible, 4438 participated and 1873 showed predisposing haplotypes (42.2%, 95% CI=40.7-43.7). The overall prevalence of celiac disease was 1.65% (95% CI, 1.34%-2.01%). Only 40% of celiac children had been diagnosed prior to the school screening. Symptoms evoking celiac disease were as common in celiac children as in controls. CONCLUSION: In this multicenter study the prevalence of celiac disease in school-age Italian children was one of the highest in the world. Determination of HLA predisposing genotypes is an easy and fast first-level screening test for celiac disease. Without a mass screening strategy, 60% of celiac patients remain currently undiagnosed in Italy.

Bioinspired photo-crosslinkable self-assembling peptides with pH-switchable "on-off" luminescence.

Significant progress has been made in peptide self-assembly over the past two decades; however, the in situ cross-linking of self-assembling peptides yielding better performing nanomaterials is still in its infancy. Indeed, self-assembling peptides (SAPs), relying only on non-covalent interactions, are mechanically unstable and susceptible to solvent erosion, greatly hindering their practical application. Herein, drawing inspiration from the biological functions of tyrosine, we present a photo-cross-linking approach for the in situ cross-linking of a tyrosine-containing LDLK12 SAP. This method is based on the ruthenium-complex-catalyzed conversion of tyrosine to dityrosine upon light irradiation. We observed a stable formation of dityrosine cross-linking starting from 5 minutes, with a maximum peak after 1 hour of UV irradiation. Furthermore, the presence of a ruthenium complex among the assembled peptide bundles bestows unusual fluorescence intensity stability up to as high as 42 °C, compared to the bare ruthenium complex. Also, due to a direct deprotonation-protonation process between the ruthenium complex and SAP molecules, the fluorescence of the photo-cross-linked SAP is capable of exhibiting "off-on-off-on" luminescence switchable from acid to basic pH. Lastly, we showed that the photo-cross-linked hydrogel exhibited enhanced mechanical stability with a storage modulus of ∼26 kPa, due to the formation of a densely entangled fibrous network of SAP molecules through dityrosine linkages. As such, this ruthenium-mediated photo-cross-linked SAP hydrogel could be useful in the design of novel tyrosine containing SAP materials with intriguing potential for biomedical imaging, pH sensing, photonics, soft electronics, and bioprinting.

A new double immunohistochemistry method to detect mucosal anti-transglutaminase IgA deposits in coeliac children.

BACKGROUND: Intestinal transglutaminase (TG2) IgA deposits represent early marker of coeliac disease (CeD) and can predict the evolution towards intestinal atrophy. AIMS: To validate a double immunohistochemistry method for the determination of intestinal TG2 IgA deposits on formalin-fixed paraffin-embedded biopsies. METHODS: Immunohistochemistry was tested on: 1) children with overt CeD [persistently positive serum IgA anti-tissue transglutaminase type 2 (TGA-IgA) with moderate or low titer, and histological findings of CeD]; 2) potential CeD (persistently positive serum TGA-IgA and normal intestinal mucosa) and 3) controls (negative serum TGA-IgA and normal intestinal mucosa). RESULTS: Samples from 61 children were analyzed (32 overt CeD, 14 potential CeD, and 15 controls). Deposits appeared as focal, multifocal, or confluent extracellular foci of red and brown staining colocalization in the sub-epithelium and around mucosal vessels. Deposits were present in all 32 children with overt CeD and in 9/14 potential CeD. Deposits were never observed in the 15 controls. Patients with higher serum level of TGA-IgA and with mucosal atrophy showed mostly a multifocal/diffuse pattern of deposits distribution. The bulb appeared most severely involved. In potential CeD deposits showed mainly a focal distribution. CONCLUSION: Our results indicate double immunohistochemistry as promising diagnostic tool to improve diagnosis of CeD.

COVID-19 and celiac disease: A pathogenetic hypothesis for a celiac outbreak.

BACKGROUND: A growing body of evidence supports the intestinal trophism of SARS-CoV-2, with ciliated cells and intestinal enterocytes being target cells because of the high expression of ACE2 and TMPRSS2. Indeed, COVID-19 promotes a "cytokine storm" in the intestinal mucosa: the resulting epithelial damage leads to increased barrier permeability, allowing the passage of gliadin in the intestinal lamina. METHODS: Based on current literature, we hypothesize the role of COVID-19 as a potential trigger factor for celiac disease in predisposed patients. CONCLUSIONS: Genetically predisposed patients could be more likely to develop celiac disease following SARS-CoV-2 infection, making COVID-19 a candidate culprit for a potential outbreak of celiac disease in the forthcoming future.

Diagnostic Value of Persistently Low Positive TGA-IgA Titers in Symptomatic Children With Suspected Celiac Disease.

OBJECTIVES: While the algorithm to diagnose celiac disease (CD) in children with elevated anti-transglutaminase IgA (TGA-IgA) titers (>10 times upper limit of normal, ULN) is well defined, the management of children with low TGA-IgA values represents a clinical challenge. We aimed to identify the diagnostic value of persistently low positive TGA-IgA titers in predicting CD in children. METHODS: We retrospectively analyzed children with symptoms or signs of CD, not eligible for a no-biopsy approach. We included children with at least 2 TGA-IgA measurements, endomysial antibody (EMA) assessment and esophagogastroduodenoscopy with biopsies. TGA-IgA values were provided as multiples of ULN. Patients were classified in groups according to median TGA-IgA values: A (TGA-IgA>1 ≤ 5 × ULN; defined as "low-positive"), B (TGA-IgA > 5 < 10 × ULN; "moderate-positive"), and C (controls). RESULTS: Data of 281 children were analyzed. Of 162 children in group A, CD was diagnosed in 142 (87.7%), whereas normal duodenal mucosa was found in 20. In group B, all 62 children (100%) received a CD diagnosis. Group C included 57 controls. EMA were undetectable in 31 (15%) of mucosal atrophy cases. On the receiver-operating characteristic curve (area under the curve = 0.910), a mean value of 1.7 ULN showed a sensitivity of 81.4% and specificity of 81.8% to predict mucosal damage. CONCLUSIONS: Repeated low or moderate TGA-IgA values (<5 ULN or <10 ULN) are good predictors of a CD diagnosis. Symptomatic children with persistently low positive TGA-IgA titers should undergo esophagogastroduodenoscopy regardless of their EMA status.

Association between Elevated TGA-IgA Titers and Older Age at Diagnosis with Absence of HBV Seroconversion in Celiac Children.

Patients with celiac disease can have a low rate of protective hepatitis B (HBV) antibody titers after vaccination. We aimed to evaluate the HBV seroconversion in celiac disease (CD) children at the time of diagnosis as well as to identify the presence of possible predictive factors. Celiac disease children were prospectively enrolled and tested for antibodies against the S protein of HBV (HBsAg) at time of diagnosis between January 2009 and February 2020. Based on the serologic response to the vaccine, "responders" and "non-responders" were identified. Statistical analysis has been performed through R statistical software (3.5.1 version, R core Team) Of 96 CD children evaluated, 41.7% (n = 40) showed non-protective or absent antibody titers against HBV. Elevated IgA-antibodies against transglutaminase 2 (TGA-IgA) values and older age at diagnosis were associated with an absent seroconversion to HBV vaccine, while presenting symptoms were not significant. An elevated prevalence of absent seroconversion to HBV vaccine exists in this cohort of CD patients at the time of disease diagnosis. Elevated TGA-IgA titers and older age at diagnosis seem to negatively predict seroconversion. Further studies are needed to identify the real profile of "non-responders", aiming to organize surveillance and eventual revaccination strategy.

Dietary Compliance and Quality of Life in Celiac Disease: A Long-Term Follow-Up of Primary School Screening-Detected Patients.

Background: Whether the diagnostic approach for celiac disease (CD) can really affect quality of life (QoL) and dietary compliance remains controversial. Aims: This study aimed to evaluate QoL and compliance to gluten-free diet (GFD) in adolescents/young adults diagnosed with CD through a screening strategy during childhood compared to age-matched CD patients diagnosed by case-finding and to assess whether follow-up at a referral center for CD influences compliance and QoL. Materials and Methods: Thirty-seven CD patients who were diagnosed by screening programs (SC-group) and 38 age-matched CD patients diagnosed due to symptoms (CF-group) were enrolled. Patients were asked to answer a questionnaire on QoL, dietary compliance, and follow-up care for CD. Results: Twenty-nine patients of the SC-group (median age 18.0 years, interquartile range [IQR] 16.0-19.0) and 31 patients of the CF-group (median age 17.0 years, IQR 15.5-18.0) completed the questionnaire. No significant difference relating adherence to the GFD and QoL was shown between the two groups. The majority (93.5%) of CF-group regularly had annual follow-up at a referral center compared to 37.9% of the SC-group (p < 0.001). Conclusion: The diagnostic strategy does not seem to impact QoL and dietary compliance. However, implementation of follow-up might still be necessary for patients identified through screening.

ESPGHAN 'biopsy-sparing' guidelines for celiac disease in children with low antitransglutaminase during COVID-19.

OBJECTIVES: Recent guidelines for celiac disease have allowed a biopsy-free approach in endomysial antibodies (EMAs) positive children with high antitransglutaminase (TGA-IgA) titer [>10 time upper limit of normal (ULN)]. Esophagogastroduodenoscopy is still necessary for diagnosis in children with lower title. Because elective pediatric endoscopy has been substantially shouted down during coronavirus disease (COVID-19) pandemic, many children remained undiagnosed - and therefore untreated - for a long time. We aimed to analyze the feasibility and accuracy of a biopsy-free approach in suspected celiac disease children with TGA-IgA values <10 ULN to facilitate the diagnostic process by avoiding endoscopy. METHODS: In this study cohort, we retrospectively analyzed all biopsy-confirmed diagnosis of celiac disease in our center (between 2014 and 2019). The positive predictive value (PPV) of TGA-IgA titers between 5 and 10 ULN and positive EMA in diagnosing celiac disease were determined. Mucosal atrophy and resolution of symptoms after gluten-free diet (GFD) were considered to confirm initial diagnosis. RESULTS: Of 430 celiac disease patients (F: 274; mean age 7.54 years) diagnosed by endoscopy, 84 (F: 46; mean age 8 years) with TGA-IgA between 5 and 10 ULN and positive EMA were identified. The PPV of TGA-IgA between 5 and 10 ULN and positive EMA was 0.93 (95% confidence interval 0.90-0.96). All these children had a symptom resolution and antibodies normalization after GFD. CONCLUSION: During the COVID-19 outbreak, a temporarily reduction of the TGA-IgA threshold for biopsy-sparing approach seems feasible in EMA positive children with TGA-IgA between 5 and 10 ULN.

Multi-omics analysis reveals the influence of genetic and environmental risk factors on developing gut microbiota in infants at risk of celiac disease.

BACKGROUND: Celiac disease (CD) is an autoimmune digestive disorder that occurs in genetically susceptible individuals in response to ingesting gluten, a protein found in wheat, rye, and barley. Research shows that genetic predisposition and exposure to gluten are necessary but not sufficient to trigger the development of CD. This suggests that exposure to other environmental stimuli early in life, e.g., cesarean section delivery and exposure to antibiotics or formula feeding, may also play a key role in CD pathogenesis through yet unknown mechanisms. Here, we use multi-omics analysis to investigate how genetic and early environmental risk factors alter the development of the gut microbiota in infants at risk of CD. RESULTS: Toward this end, we selected 31 infants from a large-scale prospective birth cohort study of infants with a first-degree relative with CD. We then performed rigorous multivariate association, cross-sectional, and longitudinal analyses using metagenomic and metabolomic data collected at birth, 3 months and 6 months of age to explore the impact of genetic predisposition and environmental risk factors on the gut microbiota composition, function, and metabolome prior to the introduction of trigger (gluten). These analyses revealed several microbial species, functional pathways, and metabolites that are associated with each genetic and environmental risk factor or that are differentially abundant between environmentally exposed and non-exposed infants or between time points. Among our significant findings, we found that cesarean section delivery is associated with a decreased abundance of Bacteroides vulgatus and Bacteroides dorei and of folate biosynthesis pathway and with an increased abundance of hydroxyphenylacetic acid, alterations that are implicated in immune system dysfunction and inflammatory conditions. Additionally, longitudinal analysis revealed that, in infants not exposed to any environmental risk factor, the abundances of Bacteroides uniformis and of metabolite 3-3-hydroxyphenylproprionic acid increase over time, while those for lipoic acid and methane metabolism pathways decrease, patterns that are linked to beneficial immunomodulatory and anti-inflammatory effects. CONCLUSIONS: Overall, our study provides unprecedented insights into major taxonomic and functional shifts in the developing gut microbiota of infants at risk of CD linking genetic and environmental risk factors to detrimental immunomodulatory and inflammatory effects. Video Abstract.

Gluten-free diet impact on dynamics of pancreatic islet-specific autoimmunity detected at celiac disease diagnosis.

OBJECTIVE: Almost 6% of celiac disease (CD) patients at diagnosis are positive for at least one of the main pancreatic islet autoantibodies that characterize type 1 diabetes (T1D). Few information, dated back to almost two decades ago, exist as to whether a gluten-free diet (GFD) could reduce the islet-specific autoimmunity detected in patients at CD diagnosis. Aim of the study was to evaluate the impact of GFD on 31 patients who presented islet-specific autoimmunity at CD diagnosis. METHODS: CD patient sera collected at diagnosis and throughout the GFD were analyzed for the main humoral autoantibodies so far identified in T1D, directed against one or more among insulin, glutamic-acid decarboxylase, tyrosine-phosphatase 2, and zinc cation-efflux transporter autoantigens. RESULTS: GFD (median duration 39 months) was associated to a decrease or disappearance of the islet-specific autoantibodies in 71% of CD patients. Almost 80% of the patients who became autoantibody-negative during the GFD were positive for only one of the islet-specific autoimmune markers at CD diagnosis, with none of them developing diabetes. Conversely, 80% of the CD patients positive at diagnosis for ≥2 islet-specific autoantibodies were still positive after more than two years of GFD, with 25% of them developing T1D. CONCLUSIONS: Various factors appear to influence, individually or in combination, the effects of the GFD on pancreatic islet-specific autoimmune response detected at CD diagnosis. These factors include the number of diabetes autoantibodies found at CD diagnosis, the adherence to the GFD, its duration and an asymptomatic clinical presentation of CD.

Type 1 diabetes, thyroid, gastric and adrenal humoral autoantibodies are present altogether in almost one third of adult celiac patients at diagnosis, with a higher frequency than children and adolescent celiac patients.

Background: No data are available on the frequency of organ-specific humoral autoimmunity at diagnosis of adult celiac disease (CD).Aim: To evaluate the humoral immunoreactivities specific of type 1 diabetes (T1D), thyroid (THD), atrophic-gastritis (AG) and Addison's (AD) diseases in 92 adult CD patients at diagnosis and 237 adult healthy subjects (CTRL).Methods: T1D, THD and AD specific autoantibodies were analyzed by radioimmunoprecipitation assays. AG autoantibodies were detected by enzyme-linked immunosorbent assay.Results: Of 92 CD patients, 31.5% were positive for at least one of the organ-specific autoantibodies investigated (p < .0001 vs CTRL). Thyroid, diabetes, gastric and adrenal-autoantibodies, that increase with age at diagnosis, were detected in 12.0%, 10.9%, 10.9%, 2.2% of CD patients, respectively. Gastric- and diabetes- rather than thyroid- and adrenal-autoimmunity seem to be specifically related to presence of CD.Conclusions: One third of adult CD patients at diagnosis is target of at least one organ-specific autoantibody. A systematic organ-specific autoantibody screening in these patients might be of value to promptly identify, prevent or treat the relative diseases.