Single-Cell RNA Sequencing of Peripheral Blood Mononuclear Cells From Pediatric Coeliac Disease Patients Suggests Potential Pre-Seroconversion Markers.

Celiac Disease (CeD) is a complex immune disorder involving villous atrophy in the small intestine that is triggered by gluten intake. Current CeD diagnosis is based on late-stage pathophysiological parameters such as detection of specific antibodies in blood and histochemical detection of villus atrophy and lymphocyte infiltration in intestinal biopsies. To date, no early onset biomarkers are available that would help prevent widespread villous atrophy and severe symptoms and co-morbidities. To search for novel CeD biomarkers, we used single-cell RNA sequencing (scRNAseq) to investigate PBMC samples from 11 children before and after seroconversion for CeD and 10 control individuals matched for age, sex and HLA-genotype. We generated scRNAseq profiles of 9559 cells and identified the expected major cellular lineages. Cell proportions remained stable across the different timepoints and health conditions, but we observed differences in gene expression profiles in specific cell types when comparing patient samples before and after disease development and comparing patients with controls. Based on the time when transcripts were differentially expressed, we could classify the deregulated genes as biomarkers for active CeD or as potential pre-diagnostic markers. Pathway analysis showed that active CeD biomarkers display a transcriptional profile associated with antigen activation in CD4+ T cells, whereas NK cells express a subset of biomarker genes even before CeD diagnosis. Intersection of biomarker genes with CeD-associated genetic risk loci pinpointed genetic factors that might play a role in CeD onset. Investigation of potential cellular interaction pathways of PBMC cell subpopulations highlighted the importance of TNF pathways in CeD. Altogether, our results pinpoint genes and pathways that are altered prior to and during CeD onset, thereby identifying novel potential biomarkers for CeD diagnosis in blood.

Early Feeding Practices and Celiac Disease Prevention: Protocol for an Updated and Revised Systematic Review and Meta-Analysis.

Uncertainty remains in regard to when, how, and in what form gluten should be introduced into the diet, particularly of infants genetically predisposed to developing celiac disease (CD). MEDLINE (PubMed), EMBASE, and Cochrane Central Register of Controlled Trials databases will be searched from inception. Randomized controlled trials (RCTs) and observational studies (cohort, case-control, or cross-sectional studies) investigating the association between early feeding practices and the risk of CD and/or CD autoimmunity will be included. In prospective studies, participants will be infants regardless of the risk of developing CD. For retrospective studies, participants will be children or adults with CD or presenting with positive serology indicative of CD. Interventions will be gluten-containing products of any type. Exposures will be breastfeeding and/or the introduction of gluten-containing products of any type. In control groups, there will be no exposure, different degrees of exposure (partial vs. exclusive breastfeeding, different amounts of gluten, etc.), or a placebo. The primary outcome measure will be CD or CD autoimmunity (i.e., anti-transglutaminase or anti-endomysial antibodies). At least two reviewers will independently assess the risk of bias using a validated risk assessment tool depending on study design. Disagreements will be resolved by discussion to achieve a consensus with the involvement of one or more additional reviewers if required. If appropriate, data will be pooled. If not, a narrative synthesis will be performed. The findings will be submitted to a peer-reviewed journal.

Celiac Disease Prevention.

Celiac disease (CD) is a common autoimmune disorder induced by ingestion of gluten in genetically susceptible individuals. Despite the prerequisite for a genetic predisposition, only a minority of the 40% of the Caucasian population that has this genetic predisposition develops the disease. Thus, environmental and/or lifestyle factors play a causal role in the development of CD. The incidence of CD has increased over the last half-century, resulting in rising interest in identifying risk factors for CD to enable primary prevention. Early infant feeding practices have been suggested as one of the factors influencing the risk of CD in genetically susceptible individuals. However, recent large prospective studies have shown that neither the timing of gluten introduction nor the duration or maintenance of breastfeeding influence the risk of CD. Also, other environmental influences have been investigated as potential risk factors, but have not led to primary prevention strategies. Secondary prevention is possible through early diagnosis and treatment. Since CD is significantly underdiagnosed and a large proportion of CD patients are asymptomatic at the time of diagnosis, secondary prevention will not identify all CD patients, as long as mass screening has not been introduced. As following a gluten-free diet is a major challenge, tertiary prevention strategies are discussed as well.

Efficacy of Home Telemonitoring versus Conventional Follow-up: A Randomized Controlled Trial among Teenagers with Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Conventional follow-up of teenagers with inflammatory bowel diseases [IBD] is done during scheduled outpatient visits regardless of how well the patient feels. We designed a telemonitoring strategy for early recognition of flares and compared its efficacy with conventional follow-up. METHODS: We used a multicentre randomized trial in patients aged 10-19 years with IBD in clinical remission at baseline. Participants assigned to telemonitoring received automated alerts to complete a symptom score and send a stool sample for measurement of calprotectin. This resulted in an individual prediction for flare with associated treatment advice and test interval. In conventional follow-up the health check interval was left to the physician's discretion. The primary endpoint was cumulative incidence of disease flares. Secondary endpoints were percentage of participants with a positive change in quality-of-life and cost-effectiveness of the intervention. RESULTS: We included 170 participants [84 telemonitoring; 86 conventional follow-up]. At 52 weeks the mean number of face-to-face visits was significantly lower in the telemonitoring group compared to conventional follow-up [3.6 vs 4.3, p < 0.001]. The incidence of flares [33 vs 34%, p = 0.93] and the proportion of participants reporting positive change in quality-of-life [54 vs 44%, p = 0.27] were similar. Mean annual cost-saving was €89 and increased to €360 in those compliant to the protocol. CONCLUSIONS: Telemonitoring is as safe as conventional follow-up, and reduces outpatient visits and societal costs. The positive impact on quality-of-life was similar in the two groups. This strategy is attractive for teenagers and families, and health professionals may be interested in using it to keep teenagers who are well out of hospital and ease pressure on overstretched outpatient services. TRIAL REGISTRATION: NTR3759 [Netherlands Trial Registry].

Gluten Introduction and the Risk of Coeliac Disease: A Position Paper by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition.

BACKGROUND: The European Society for Paediatric Gastroenterology, Hepatology and Nutrition recommended in 2008, based on observational data, to avoid both early (<4 months) and late (≥7 months) introduction of gluten and to introduce gluten while the infant is still being breast-fed. New evidence prompted ESPGHAN to revise these recommendations. OBJECTIVE: To provide updated recommendations regarding gluten introduction in infants and the risk of developing coeliac disease (CD) during childhood. SUMMARY: The risk of inducing CD through a gluten-containing diet exclusively applies to persons carrying at least one of the CD risk alleles. Because genetic risk alleles are generally not known in an infant at the time of solid food introduction, the following recommendations apply to all infants, although they are derived from studying families with first-degree relatives with CD. Although breast-feeding should be promoted for its other well-established health benefits, neither any breast-feeding nor breast-feeding during gluten introduction has been shown to reduce the risk of CD. Gluten may be introduced into the infant's diet anytime between 4 and 12 completed months of age. In children at high risk for CD, earlier introduction of gluten (4 vs 6 months or 6 vs 12 months) is associated with earlier development of CD autoimmunity (defined as positive serology) and CD, but the cumulative incidence of each in later childhood is similar. Based on observational data pointing to the association between the amount of gluten intake and risk of CD, consumption of large quantities of gluten should be avoided during the first weeks after gluten introduction and during infancy. The optimal amounts of gluten to be introduced at weaning, however, have not been established.

Research and the promotion of child health: a position paper of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition.

Children comprise one-fifth of Europe's population. Promoting child health and development is of key importance for society and its future. This position paper highlights opportunities of investing in gastrointestinal, liver, and nutritional research to promote child health and delineates priorities for research. Investing in child health plays a key role in the promotion of population health, well-being, and disease prevention lifelong, with large health economic benefits. Major opportunities for improving knowledge and translational application arise from recent scientific and technological developments, for example, the long-term impact of early environmental cues interacting with genes. Personalised approaches to therapy and prevention should be enhanced. Deciphering the microbiome and its effects on functions can help in promoting long-term health. Epigenetic research can help to understand how early environmental factors influence later gastrointestinal and hepatic health and disease. A linked nutrition and physical activity strategy can promote health and prevent nutritional deficiencies, inactivity, and chronic noncommunicable diseases, such as diabetes, to ensure optimal health and cognition. Special attention should be devoted to populations with low socioeconomic status, migrant background, and ethnic minorities, and to critical life periods, including pregnancy, lactation, infancy, and childhood. Improved understanding of optimal nutrition and on maintaining gut and liver homeostasis throughout childhood will help prevent chronic diseases in later life.

Fine mapping of the celiac disease-associated LPP locus reveals a potential functional variant.

Using the Immunochip for genotyping, we identified 39 non-human leukocyte antigen (non-HLA) loci associated to celiac disease (CeD), an immune-mediated disease with a worldwide frequency of ∼1%. The most significant non-HLA signal mapped to the intronic region of 70 kb in the LPP gene. Our aim was to fine map and identify possible functional variants in the LPP locus. We performed a meta-analysis in a cohort of 25 169 individuals from six different populations previously genotyped using Immunochip. Imputation using data from the Genome of the Netherlands and 1000 Genomes projects, followed by meta-analysis, confirmed the strong association signal on the LPP locus (rs2030519, P = 1.79 × 10(-49)), without any novel associations. The conditional analysis on this top SNP-indicated association to a single common haplotype. By performing haplotype analyses in each population separately, as well as in a combined group of the four populations that reach the significant threshold after correction (P < 0.008), we narrowed down the CeD-associated region from 70 to 2.8 kb (P = 1.35 × 10(-44)). By intersecting regulatory data from the ENCODE project, we found a functional SNP, rs4686484 (P = 3.12 × 10(-49)), that maps to several B-cell enhancer elements and a highly conserved region. This SNP was also predicted to change the binding motif of the transcription factors IRF4, IRF11, Nkx2.7 and Nkx2.9, suggesting its role in transcriptional regulation. We later found significantly low levels of LPP mRNA in CeD biopsies compared with controls, thus our results suggest that rs4686484 is the functional variant in this locus, while LPP expression is decreased in CeD.

Determination of IgG and IgA antibodies against native gliadin is not helpful for the diagnosis of coeliac disease in children up to 2 years old.

OBJECTIVE: Assays for antibodies against native gliadin (anti-nGli) are still often assumed to perform better in the diagnosis of coeliac disease in young children than tests for antibodies to deamidated gliadin (anti-dGli), tissue transglutaminase (anti-tTG), and endomysium (EmA). We compared the performance of assays for anti-nGli, anti-dGli, anti-tTG, and EmA in this age group. METHODS: We investigated retrospectively 184 children (42 with coeliac disease under normal diet and 142 controls) up to 2 years of age. Immunoglobulin (Ig) A- and IgG-anti-dGli, IgA- and IgG-anti-nGli, IgA- and IgG-anti-tTG, and IgA-EmA were measured in serum. Areas under receiver operating characteristics curves, sensitivities, specificities, positive and negative predictive values, positive and negative likelihood ratios, as well as diagnostic odds ratios were calculated. RESULTS: From all of the tests investigated, only assays for IgG-anti-dGli, IgA-anti-tTG, and IgA-EmA had high specificity (≥ 0.96) connected with high sensitivity (≥ 0.86), with high positive predictive values (≥ 0.52 and ≥ 0.69 at pretest probabilities of 0.05 and 0.1, respectively) and negative predictive values (≥ 0.99 and ≥ 0.98 at pretest probabilities of 0.05 and 0.1, respectively). These assays also showed high positive likelihood ratio (≥ 24) at low negative likelihood ratio (≤ 0.15) and high diagnostic odds ratios (≥ 136). CONCLUSIONS: Our results do not support the use of assays of anti-nGli to diagnose coeliac disease in young children. IgA-anti-tTG, IgA-EmA, and IgG-anti-dGli perform better than anti-nGli.

A toddler with recurrent oral and genital ulcers.

In western countries, when a child presents with recurrent oral ulcers and colitis, the diagnosis of Crohn's disease is mostly made. In our patient, the diagnosis was Behçet's disease with gastrointestinal manifestations. Behçet's disease with gastrointestinal manifestations has a similar clinical presentation to Crohn's disease, but there is more organ involvement and the prognosis is more severe in the former. Because there is limited experience in the treatment of Behçet's disease in the paediatric population, successful and unsuccessful treatment modalities in both paediatric and adult populations should be reported.

The HLA-DQ2 gene dose effect in celiac disease is directly related to the magnitude and breadth of gluten-specific T cell responses.

In patients with celiac disease, inflammatory T cell responses to HLA-DQ2-bound gluten peptides are thought to cause disease. Two types of HLA-DQ2 molecules exist, termed HLA-DQ2.5 and HLA-DQ2.2. Whereas HLA-DQ2.5 predisposes to celiac disease, HLA-DQ2.2 does not. We now provide evidence that the disease-associated HLA-DQ2.5 molecule presents a large repertoire of gluten peptides, whereas the non-disease-associated HLA-DQ2.2 molecule can present only a subset of these. Moreover, gluten presentation by HLA-DQ2 homozygous antigen-presenting cells was superior to presentation by HLA-DQ2/non-DQ2 heterozygous antigen-presenting cells in terms of T cell proliferation and cytokine secretion. Gluten presentation by HLA-DQ2.5/2.2 heterozygous antigen-presenting cells induced intermediate T cell stimulation. These results correlated with peptide binding to the antigen-presenting cells. Finally, we demonstrate that HLA-DQ trans dimers formed in HLA-DQ2.5/2.2 heterozygous individuals have properties identical with HLA-DQ2.5 dimers. Our findings explain the strongly increased risk of disease development for HLA-DQ2.5 homozygous and HLA-DQ2.2/2.5 heterozygous individuals, and they are indicative of a quantitative model for disease development, where HLA-DQ expression and the available number of T cell-stimulatory gluten peptides are critical limiting factors. This model may have important implications for disease prevention.

The gluten response in children with celiac disease is directed toward multiple gliadin and glutenin peptides.

BACKGROUND & AIMS: Gluten (GLU)-specific T-cell responses in HLA-DQ2 positive adult celiac disease (CD) patients are directed to an immunodominant alpha-gliadin (GLIA) peptide that requires deamidation for T-cell recognition. The aim of the current study was to determine which GLU peptide(s) are involved early in disease. METHODS: We have characterized the GLU-specific T-cell response in HLA-DQ2 positive children with recent onset CD. RESULTS: We found that 50% of these patients do not respond to the alpha-GLIA peptide but to a diverse set of GLIA and glutenin (GLT) peptides, including 6 novel epitopes. Moreover, individual patients respond to distinct (combinations of) GLU peptides. T-cell cross-reactivity toward homologous GLIA and GLT peptides was observed, which might play a role in the initial spreading of the GLU-specific T-cell response. Although all pediatric patients displayed deamidation-dependent responses, deamidation-independent responses were found in the majority of patients as well. Finally, T-cell responses to 3 of these novel GLU peptides were found in adult CD patients. CONCLUSIONS: The diversity of the GLU-specific T-cell response is far greater than was previously appreciated. Both adult and young CD patients can respond to a diverse repertoire of GLU peptides. The observation that T-cell responses to 3 of the novel peptides are independent of deamidation indicates that T-cell responses can be initiated toward native GLU peptides. The possibility that deamidation drives the GLU response toward immunodominant T-cell stimulatory peptides after disease initiation is discussed.