Incidence of Pediatric Celiac Disease Varies by Region.

INTRODUCTION: The Environmental Determinants of Diabetes in the Young study follows an HLA risk selected birth cohort for celiac disease (CD) development using a uniform protocol. Children under investigation come from 6 different regions within Europe and the United States. Our aim was to identify regional differences in CD autoimmunity and CD cumulative incidence for children born between 2004 and 2010. METHODS: Children (n = 6,628) with DQ2.5 and/or DQ8.1 were enrolled prospectively from birth in Georgia, Washington, Colorado, Finland, Germany, and Sweden. Children underwent periodic study screening for tissue transglutaminase antibodies and then CD evaluation per clinical care. Population-specific estimates were calculated by weighting the study-specific cumulative incidence with the population-specific haplogenotype frequencies obtained from large stem cell registries from each site. RESULTS: Individual haplogenotype risks for CD autoimmunity and CD varied by region and affected the cumulative incidence within that region. The CD incidence by age 10 years was highest in Swedish children at 3%. Within the United States, the incidence by age 10 years in Colorado was 2.4%. In the model adjusted for HLA, sex, and family history, Colorado children had a 2.5-fold higher risk of CD compared to Washington. Likewise, Swedish children had a 1.4-fold and 1.8-fold higher risk of CD compared with those in Finland and Germany, respectively. DISCUSSION: There is high regional variability in cumulative incidence of CD, which suggests differential environmental, genetic, and epigenetic influences even within the United States. The overall high incidence warrants a low threshold for screening and further research on region-specific CD triggers.

Prevalence of vomiting and nausea and associated factors after chronic and acute gluten exposure in celiac disease.

BACKGROUND: Vomiting and nausea seem to be relatively specific symptoms related to gluten ingestion in treated celiac disease. However, the overall prevalence and associated factors of these symptoms after chronic gluten exposure at celiac disease diagnosis and acute re-exposure during gluten challenge remain obscure. METHODS: Medical data on 815 adult celiac disease patients were collected at diagnosis from the medical records and through supplementary interviews. An additional 74 patients underwent a three-day (10 g/day) gluten challenge (wheat, barley, rye or a combination of the three grains) while in remission. Prevalence of vomiting/nausea and associated factors were evaluated in both cohorts. A literature review was conducted to summarize earlier studies. RESULTS: Twenty-eight (3%) patients presented with vomiting at diagnosis. They were less often screen-detected and suffered from extra-intestinal symptoms, and had more often abdominal pain (71% vs. 49%, p = 0.021), diarrhea (61% vs. 40%, p = 0.031), weight loss (36% vs. 17%, p = 0.019) and childhood symptoms (61% vs. 33%, p = 0.002) than those without vomiting (n = 787). The groups were comparable in other clinical-demographic data and in genetic, serological, and histological findings. Short-term gluten challenge provoked vomiting/nausea in 14/74 (19%) patients. They consumed gluten-free oats less often than those without these symptoms (64% vs. 92%, p = 0.017), whereas the groups did not differ in clinical-demographic features at diagnosis, presence of comorbidities, duration of gluten-free diet, or in other symptoms or grain used ingested during the challenge. According to the literature, prevalence of vomiting/nausea at celiac disease diagnosis has varied 3-46% and during gluten challenge 13-61%. CONCLUSIONS: In chronic gluten exposure at celiac disease diagnosis, vomiting was associated with other gastrointestinal symptoms and onset of symptoms already in childhood, whereas regular consumption of oats may increase the tolerance against vomiting/nausea after acute re-exposure in treated celiac disease.

Antibody Responses to Transglutaminase 3 in Dermatitis Herpetiformis: Lessons from Celiac Disease.

Dermatitis herpetiformis (DH) is the skin manifestation of celiac disease, presenting with a blistering rash typically on the knees, elbows, buttocks and scalp. In both DH and celiac disease, exposure to dietary gluten triggers a cascade of events resulting in the production of autoantibodies against the transglutaminase (TG) enzyme, mainly TG2 but often also TG3. The latter is considered to be the primary autoantigen in DH. The dynamics of the development of the TG2-targeted autoimmune response have been studied in depth in celiac disease, but the immunological process underlying DH pathophysiology is incompletely understood. Part of this process is the occurrence of granular deposits of IgA and TG3 in the perilesional skin. While this serves as the primary diagnostic finding in DH, the role of these immunocomplexes in the pathogenesis is unknown. Intriguingly, even though gluten-intolerance likely develops initially in a similar manner in both DH and celiac disease, after the onset of the disease, its manifestations differ widely.

Toward Xeno-Free Differentiation of Human Induced Pluripotent Stem Cell-Derived Small Intestinal Epithelial Cells.

The small intestinal epithelium has an important role in nutrition, but also in drug absorption and metabolism. There are a few two-dimensional (2D) patient-derived induced pluripotent stem cell (iPSC)-based intestinal models enabling easy evaluation of transcellular transport. It is known that animal-derived components induce variation in the experimental outcomes. Therefore, we aimed to refine the differentiation protocol by using animal-free components. More specifically, we compared maturation of 2D-cultured iPCSs toward small intestinal epithelial cells when cultured either with or without serum, and either on Geltrex or on animal-free, recombinant laminin-based substrata. Differentiation status was characterized by qPCR, immunofluorescence imaging, and functionality assays. Our data suggest that differentiation toward definitive endoderm is more efficient without serum. Both collagen- and recombinant laminin-based coating supported differentiation of definitive endoderm, posterior definitive endoderm, and small intestinal epithelial cells from iPS-cells equally well. Small intestinal epithelial cells differentiated on recombinant laminin exhibited slightly more enterocyte specific cellular functionality than cells differentiated on Geltrex. Our data suggest that functional small intestinal epithelial cells can be generated from iPSCs in serum-free method on xeno-free substrata. This method is easily converted to an entirely xeno-free method.

Independent and cumulative coeliac disease-susceptibility loci are associated with distinct disease phenotypes.

The phenotype of coeliac disease varies considerably for incompletely understood reasons. We investigated whether established coeliac disease susceptibility variants (SNPs) are individually or cumulatively associated with distinct phenotypes. We also tested whether a polygenic risk score (PRS) based on genome-wide associated (GWA) data could explain the phenotypic variation. The phenotypic association of 39 non-HLA coeliac disease SNPs was tested in 625 thoroughly phenotyped coeliac disease patients and 1817 controls. To assess their cumulative effects a weighted genetic risk score (wGRS39) was built, and stratified by tertiles. In our PRS model in cases, we took the summary statistics from the largest GWA study in coeliac disease and tested their association at eight P value thresholds (PT) with phenotypes. Altogether ten SNPs were associated with distinct phenotypes after correction for multiple testing (PEMP2 ≤ 0.05). The TLR7/TLR8 locus was associated with disease onset before and the SH2B3/ATXN2, ITGA4/UBE2E3 and IL2/IL21 loci after 7 years of age. The latter three loci were associated with a more severe small bowel mucosal damage and SH2B3/ATXN2 with type 1 diabetes. Patients at the highest wGRS39 tertiles had OR > 1.62 for having coeliac disease-related symptoms during childhood, a more severe small bowel mucosal damage, malabsorption and anaemia. PRS was associated only with dermatitis herpetiformis (PT = 0.2, PEMP2 = 0.02). Independent coeliac disease-susceptibility loci are associated with distinct phenotypes, suggesting that genetic factors play a role in determining the disease presentation. Moreover, the increased number of coeliac disease susceptibility SNPs might predispose to a more severe disease course.

Differences Between Familial and Sporadic Celiac Disease.

BACKGROUND: It is not known if genetic background, characteristics at diagnosis, physical and psychological well-being, and adherence to a gluten-free diet are comparable between patients with familial or sporadic celiac disease. These issues were investigated in a follow-up study. METHODS: Altogether 1064 patients were analyzed for celiac disease-associated serology, predisposing HLA-DQ, and non-HLA genotypes. Medical data were collected from patient records and supplementary interviews. Current symptoms and quality of life were further evaluated with the Gastrointestinal Symptom Rating Scale (GSRS), the Psychological General Well-Being questionnaire (PGWB), and Short Form 36 (SF-36) questionnaires. RESULTS: Familial and sporadic groups differed (P < 0.001) in the reason for diagnosis and clinical presentation at diagnosis, familial patients being more often screen-detected (26% vs. 2%, P < 0.001) and having less often gastrointestinal (49% vs. 69%) and severe symptoms (47% vs. 65%). The groups were comparable in terms of histological damage, frequency of malabsorption, comorbidities, childhood diagnoses, and short-term treatment response. At the time of the study, familial cases reported fewer symptoms (21% vs. 30%, P = 0.004) and lower prevalence of all (78% vs. 86%, P = 0.007), neurological (10% vs. 15%, P = 0.013), and dermatological (9% vs. 17%, P = 0.001) comorbidities. Dietary adherence and GSRS scores were comparable, but familial cases had better quality of life according to PGWB and SF-36. High-risk genotype HLA-DQ2.5/DQ2.5 was more frequent among familial cases, and four non-HLA SNPs were associated with familial celiac disease. CONCLUSIONS: Despite the greater proportion of high-risk genotypes, familial cases had milder symptoms at presentation than did sporadic cases. Worse experience of symptoms and poorer quality of life in sporadic disease indicate a need for intensified support.

Metagenomics of the faecal virome indicate a cumulative effect of enterovirus and gluten amount on the risk of coeliac disease autoimmunity in genetically at risk children: the TEDDY study.

OBJECTIVE: Higher gluten intake, frequent gastrointestinal infections and adenovirus, enterovirus, rotavirus and reovirus have been proposed as environmental triggers for coeliac disease. However, it is not known whether an interaction exists between the ingested gluten amount and viral exposures in the development of coeliac disease. This study investigated whether distinct viral exposures alone or together with gluten increase the risk of coeliac disease autoimmunity (CDA) in genetically predisposed children. DESIGN: The Environmental Determinants of Diabetes in the Young study prospectively followed children carrying the HLA risk haplotypes DQ2 and/or DQ8 and constructed a nested case-control design. From this design, 83 CDA case-control pairs were identified. Median age of CDA was 31 months. Stool samples collected monthly up to the age of 2 years were analysed for virome composition by Illumina next-generation sequencing followed by comprehensive computational virus profiling. RESULTS: The cumulative number of stool enteroviral exposures between 1 and 2 years of age was associated with an increased risk for CDA. In addition, there was a significant interaction between cumulative stool enteroviral exposures and gluten consumption. The risk conferred by stool enteroviruses was increased in cases reporting higher gluten intake. CONCLUSIONS: Frequent exposure to enterovirus between 1 and 2 years of age was associated with increased risk of CDA. The increased risk conferred by the interaction between enteroviruses and higher gluten intake indicate a cumulative effect of these factors in the development of CDA.

Diagnostic findings and long-term prognosis in children with anemia undergoing GI endoscopies.

BACKGROUND AND AIMS: Intestinal diseases are regarded as a common cause of anemia, but the diagnostic outcomes of children with anemia undergoing endoscopic investigations are unclear. We investigated this issue in a large cohort of children. METHODS: Indications for and findings of consecutive gastrointestinal (GI) endoscopies were collected. Clinical presentation and diagnostic outcomes were compared between anemic and nonanemic patients and between anemic patients with and without a diagnosis. Diagnoses received during follow-up were collected. RESULTS: Of 2395 consecutive endoscopies, 251 children with and 613 children without anemia had undergone either diagnostic esophagogastroduodenoscopy (EGD) (51.4% and 51.4%, respectively), colonoscopy (4.0% and 11.4%), or both (45.8% and 37.8%). Children with anemia more often received diagnoses (72.9% vs 39.3%; odds ratio [OR], 4.18; 95% confidence interval [CI], 3.03-5.77), particularly of celiac disease (26.3% vs 15.5%, P < .001) and of inflammatory bowel disease (31.1% vs 9.1%, P < .001), than did nonanemic children. The diagnosis in anemic patients was predicted by age 5 to 12 years (OR, 3.52; 95% CI, 1.27-9.75), presence of diarrhea (OR, 2.04; 95% CI, 1.07-3.90), melena/hematochezia (OR, 2.40; 95% CI, 1.17-4.92), poor growth (OR, 3.94; 95% CI, 1.70-9.15), positive celiac serology (OR, 11.81; 95% CI, 3.47-40.12), high calprotectin (OR, 12.86; 95% CI, 4.00-41.32), hypersedimentation (OR, 2.65; 95% CI, 1.29-5.44), and hypoalbuminemia (OR, 5.05; 95% CI, 1.56-16.34). Thirty children with anemia (12.0%) had no GI symptoms, and 22 of them (73.3%) were given diagnoses at the time of the endoscopies. All 22 had additional laboratory abnormalities, whereas these were present in only 2 of 8 undiagnosed children. None of them was diagnosed later in the follow-up of up to 11 years, in contrast to 4 (6.7%) of all anemic and 33 (8.9%) of all nonanemic patients. CONCLUSIONS: Anemia increased the probability of being given a diagnosis, emphasizing its importance as an alarm symptom. However, endoscopies in anemic patients without additional symptoms or laboratory abnormalities seldom improved the diagnostic yield.

Severity of Villous Atrophy at Diagnosis in Childhood Does Not Predict Long-term Outcomes in Celiac Disease.

OBJECTIVES: Current pediatric guidelines allow noninvasive diagnosis of celiac disease in selected children. We investigated in a large cohort study whether the severity of villous atrophy at diagnosis is associated with clinical characteristics or long-term health outcomes, thus having a prognostic significance. METHODS: Comprehensive medical data on 906 children with celiac disease were analyzed. Long-term health outcomes of 503 adult patients diagnosed in childhood were moreover assessed with a specific study questionnaire and validated Gastrointestinal Symptom Rating Scale (GSRS) and Psychological General Well-Being (PGWB) questionnaires. Patients were classified into 3 groups according to the severity of villous atrophy at diagnosis, and all variables were compared. RESULTS: Altogether 34% of the patients had partial, 40% subtotal, and 26% total villous atrophy. Children with milder lesions were diagnosed more recently (median year 2007 vs 2006 vs 2001, respectively, P < 0.001), more often by screening (30% vs 25% vs 17%, P < 0.001) and they suffered less often from anemia (16% vs 21% vs 32%, P < 0.001) and growth disturbances (22% vs 36% vs 54%, P < 0.001) and had lower transglutaminase-2 antibody levels (median 64 U/L vs 120 U/L vs 120 U/L, P < 0.001). There was no difference in other disease features.Altogether 212 adults diagnosed in childhood completed the questionnaires. Severity of villous atrophy at childhood diagnosis did not predict presence of complications or comorbidities, persistent symptoms, and self-perceived health, quality of life or adherence to a gluten-free diet in adulthood. CONCLUSION: Presence of advanced villous atrophy at diagnosis is associated with more severe clinical characteristics but not with poorer long-term health and treatment outcomes.

Dietary Factors and Mucosal Immune Response in Celiac Disease Patients Having Persistent Symptoms Despite a Gluten-free Diet.

GOALS: The aim of this study was to investigate the role of dietary factors, distinct small-bowel mucosal immune cell types, and epithelial integrity in the perpetuation of gastrointestinal symptoms in treated celiac disease patients. BACKGROUND: For unexplained reasons, many celiac disease patients suffer from persistent symptoms, despite a strict gluten-free diet (GFD) and recovered intestinal mucosa. STUDY: We compared clinical and serological data and mucosal recovery in 22 asymptomatic and 25 symptomatic celiac patients on a long-term GFD. The density of CD3 and γδ intraepithelial lymphocytes (IELs), CD25 and FOXP3 regulatory T cells, and CD117 mast cells, and the expression of tight junction proteins claudin-3 and occludin, heat shock protein 60, interleukin 15, and Toll-like receptor 2 and 4 were evaluated in duodenal biopsies. RESULTS: All subjects kept a strict GFD and had negative celiac autoantibodies and recovered mucosal morphology. The asymptomatic patients had higher mean fiber intake (20.2 vs. 15.2 g/d, P=0.028) and density of CD3 IELs (59.3 vs. 45.0 cell/mm, P=0.045) than those with persistent symptoms. There was a similar but nonsignificant trend in γδ IELs (17.9 vs. 13.5, P=0.149). There were no differences between the groups in other parameters measured. CONCLUSIONS: Low fiber intake may predispose patients to persistent symptoms in celiac disease. There were no differences between the groups in the markers of innate immunity, epithelial stress or epithelial integrity. A higher number of IELs in asymptomatic subjects may indicate that the association between symptoms and mucosal inflammation is more complicated than previously thought.

Small-intestinal TG2-specific plasma cells at different stages of coeliac disease.

BACKGROUND: In coeliac disease, ingestion of gluten induces the production of transglutaminase 2 (TG2)-targeted autoantibodies by TG2-specific plasma cells present at high frequency in the small intestinal mucosa in untreated disease. During treatment with a gluten-free diet (GFD), the number of these cells decreases considerably. It has not been previously investigated whether the cells are also present prior to development of villous atrophy, or in non-responsive patients and those with dietary lapses. We aimed to define the frequency of small bowel mucosal TG2-specific plasma cells in coeliac disease patients with varying disease activity, and to investigate whether the frequency correlates with serum and small intestinal TG2-targeting antibodies as well as mucosal morphology and the number of intraepithelial lymphocytes. RESULTS: Mucosal TG2-specific plasma cells were found in 79% of patients prior to development of mucosal damage, in all patients with villous atrophy, and in 63% of the patients after 1 year on GFD. In these disease stages, TG2-specific plasma cells accounted for median of 2.3, 4.3, and 0.7% of all mucosal plasma cells, respectively. After long-term treatment, the cells were present in 20% of the patients in clinical remission (median 0%) and in 60% of the patients with poor dietary adherence (median 5.8%). In patients with non-responsive coeliac disease despite strict GFD, the cells were found in only one (9%) subject; the cells accounted for 2.4% of all plasma cells. A positive correlation between the percentage of TG2-specific plasma cells and serum TG2 antibody levels (rS = 0.69, P < 0.001) and the intensity of mucosal TG2-targeting IgA deposits (rS = 0.43, P < 0.001) was observed. CONCLUSIONS: Our results show that TG2-specific plasma cells are already detectable prior to villous atrophy, and that generally their frequency increases during overt disease. By contrast, on GFD, the percentage of these cells decreases. Overall, the presence of TG2-specific plasma cells in the small bowel mucosa mirrors the presence of gluten in the diet, but the frequency is not always parallel to the level of serum or intestinal TG2 antibodies. These findings increase the knowledge about the development of the TG2 plasma cell responses especially in the early phases of coeliac disease.

Polycomb Repressive Complex 2 Enacts Wnt Signaling in Intestinal Homeostasis and Contributes to the Instigation of Stemness in Diseases Entailing Epithelial Hyperplasia or Neoplasia.

Canonical Wnt/ß-catenin signaling regulates the homeostasis of intestinal epithelium by controlling the balance between intestinal stem cell self-renewal and differentiation but epigenetic mechanisms enacting the process are not known. We hypothesized that epigenetic regulator, Polycomb Repressive Complex-2 (PRC2), is involved in Wnt-mediated epithelial homeostasis on the crypt-villus axis and aberrancies therein are implicated both in celiac disease and in intestinal malignancies. We found that PRC2 establishes repressive crypt and villus specific trimethylation of histone H3 lysine 27 (H3K27me3) signature on genes responsible for, for example, nutrient transport and cell killing in crypts and, for example, proliferation and differentiation in mature villi, suggesting that PRC2 facilitates the Wnt-governed intestinal homeostasis. When celiac patients are on gluten-containing diet PRC2 is out-of-bounds active and consequently its target genes were found affected in intestinal epithelium. Significant set of effective intestinal PRC2 targets are also differentially expressed in colorectal adenoma and carcinomas. Our results suggest that PRC2 gives rise and maintains polar crypt and villus specific H3K27me3 signatures. As H3K27me3 is a mark enriched in developmentally important genes, identified intestinal PRC2 targets are possibly imperative drivers for enterocyte differentiation and intestinal stem cell maintenance downstream to Wnt-signaling. Our work also elucidates the mechanism sustaining the crypt hyperplasia in celiac disease and suggest that PRC2-dependent fostering of epithelial stemness is a common attribute in intestinal diseases in which epithelial hyperplasia or neoplasia prevails. Finally, this work demonstrates that in intestine PRC2 represses genes having both pro-stemness and pro-differentiation functions, fact need to be considered when designing epigenetic therapies including PRC2 as a drug target. Stem Cells 2017;35:445-457.

Ex vivo Culture of Duodenal Biopsies from Patients with Dermatitis Herpetiformis Indicates that Transglutaminase 3 Antibody Production Occurs in the Gut.

Coeliac disease and dermatitis herpetiformis (DH) are characterized by autoantibodies targeting transglutaminase (TG)2 and TG3, respectively. Previous studies show that TG2 antibodies are produced in the gut and can be assessed in organ culture of small-intestinal biopsies from patients with coeliac disease. Thus far, no studies have investigated TG3 antibodies in organ culture of biopsies from patients with DH, or exploited the method in DH. The aim of this study was to investigate TG3 and TG2 antibody responses in serum and small-intestinal biopsies from patients with DH with active disease, and from those in remission. The majority of patients with DH were negative for both serum and organ culture medium TG2-targeting antibodies. Surprisingly, patients with active DH secreted TG3 antibodies into the culture medium despite seronegativity. In patients secreting high levels of TG3 antibodies into the culture medium, we also detected TG3-antibody-positive cells in the small-intestinal mucosa. These findings suggest that TG3 antibodies can be investigated in the organ culture system and that their secretion occurs in the small intestine, especially in active DH.

Transglutaminase 2-specific coeliac disease autoantibodies induce morphological changes and signs of inflammation in the small-bowel mucosa of mice.

Coeliac disease is hallmarked by an abnormal immune reaction against ingested wheat-, rye- and barley-derived gluten and the presence of transglutaminase 2 (TG2)-targeted autoantibodies. The small-bowel mucosal damage characteristic of the disorder develops gradually from normal villus morphology to inflammation and finally to villus atrophy with crypt hyperplasia. Patients with early-stage coeliac disease have TG2-autoantibodies present in serum and small-intestinal mucosa and they may already suffer from abdominal symptoms before the development of villus atrophy. Previously, we have shown that intraperitoneal injections of coeliac patient-derived sera or purified immunoglobulin fraction into mice induce a condition mimicking early-stage coeliac disease. In the current study, we sought to establish whether recombinantly produced patient-derived TG2-targeted autoantibodies are by themselves sufficient for the development of such an experimentally induced condition in immune-compromised mice. Interestingly, mice injected with coeliac patient TG2-antibodies had altered small-intestinal mucosal morphology, increased lamina propria cellular infiltration and disease-specific autoantibodies deposited in the small bowel, but did not evince clinical features of the disease. Thus, coeliac patient-derived TG2-specific autoantibodies seem to be sufficient for the induction of subtle small-bowel mucosal alterations in mice, but the development of clinical features probably requires additional factors such as other antibody populations relevant in coeliac disease.

Anemia in Pediatric Celiac Disease: Association With Clinical and Histological Features and Response to Gluten-free Diet.

GOALS: The aim of the present study was to compare clinical, serological, and histological manifestations between children with anemia and without anemia at celiac disease (CD) diagnosis. BACKGROUND: Despite being a common finding, the association between the presence of anemia and clinicohistopathological presentation of CD in children remains obscure. STUDY: A total of 455 patients with CD <18 years of age were divided into those with anemia and those without anemia at diagnosis. The groups underwent comparisons of a variety of clinical, serological, and laboratory parameters and severity of small-bowel mucosal damage. Furthermore, adherence and clinical and serological response to the gluten-free diet (GFD) were compared. RESULTS: Anemia was detected in 18.0% of the patients. Children with anemia had higher values for transglutaminase 2 antibodies (120.0 U/L vs 88.0 U/L, P < 0.001) and, by definition, lower values for hemoglobin (10.5 g/dL vs 12.8 g/dL, P < 0.001) and other iron parameters. They were also less often screen-detected (13.4% vs 34.6%), had more severe histological damage (P = 0.048), and poorer dietary adherence (78.3% vs 87.5%, P = 0.035) than the patients without anemia. A total of 92% of the patients recovered from anemia after a median of 1 year on a GFD, but hemoglobin values remained significantly lower compared with the nonanemic group (12.5 g/dL vs 13.2 g/dL, P = 0.045). There was no difference between the groups in the clinical and serological response to the GFD (P = 0.318). CONCLUSIONS: Anemia at CD diagnosis is associated with more severe histological and serological presentation in children. Furthermore, low hemoglobin may not fully recover even after a median of 1 year on a strict GFD.

Anemia and Iron Deficiency in Children With Potential Celiac Disease.

OBJECTIVES: Active screening for celiac disease frequently detects seropositive children with normal villous morphology (potential celiac disease). It remains unclear whether these subjects should be treated. We here investigated the prevalence of anemia and iron deficiency in children with potential and mucosal atrophy celiac disease. METHODS: The prospective study involved 19 children with potential disease, 67 with partial or subtotal villous atrophy (P/SVA), and 16 with total villous atrophy (TVA). Twenty-three healthy children comprised the control group. The groups were compared for various clinical, histological, and laboratory parameters and hepcidin. RESULTS: The prevalence of abnormal parameters was as follows (controls, potential celiac disease, P/SVA, and TVA, respectively): anemia 0%, 15%, 22%, and 63%; low iron 5%, 0%, 14%, and 50%; increased transferrin receptor 1 5%, 16%, 20%, and 47%; low ferritin 0%, 21%, 35%, and 87%; and low transferrin saturation 10%, 11%, 41%, and 71%. One subject had low folate and none had low vitamin B12. The median values for hemoglobin, total iron, ferritin, and transferrin saturation were significantly lower and transferrin receptor 1 values higher in TVA group compared with other groups. After a median of 7 months on a gluten-free diet hemoglobin, total iron, ferritin, and albumin in children with P/SVA exceeded the baseline values in the potential celiac disease group. CONCLUSIONS: The development of anemia and iron deficiency in celiac disease is a continuum and may already be present in children with normal villous morphology, advocating an early diagnosis and possible dietary treatment of these patients.

Dermatitis Herpetiformis Refractory to Gluten-free Dietary Treatment.

Dermatitis herpetiformis (DH) is a blistering skin disease, which is regarded as an extra-intestinal manifestation of coeliac disease. Refractory cases of coeliac disease, that do not respond to a gluten-free diet and which carry an increased risk of lymphoma, are well-known in coeliac disease. To determine whether refractory cases of DH with active rash and persistent small bowel atrophy occur we analysed our series of 403 patients with DH. Seven (1.7%) patients, who had been on a gluten-free diet for a mean of 16 years, but who still required dapsone to treat the symptoms of DH, were identified. Of these, one patient died from mucinous adenocarcinoma before re-examination. At re-examination skin immunoglobulin A (IgA) deposits were found in 5/6 refractory and 3/16 control DH patients with good dietary response. Small bowel mucosa was studied at re-examination from 5 refractory and 8 control DH patients and was normal in all 5 refractory and 7/8 control DH patients. One refractory DH patient died from adenocarcinoma, but no lymphoma developed in any of the patients. This study documents for the first time refractory DH, in which the rash is non-responsive to a gluten-free diet, but the small bowel mucosa heals. This differs from refractory coeliac disease, in which the small bowel mucosa does not heal on a gluten-free diet.

Novel treatments for celiac disease: glutenases and beyond.

Currently, the only effective treatment for celiac disease is a strict lifelong gluten-free diet. However, gluten-free dieting is restrictive, difficult to maintain and nutritionally less than optimal. The improved knowledge on celiac disease pathogenesis has enabled researchers to suggest alternative strategies to treat the disorder. The drug development poses a challenge as any novel drug for celiac disease should be simultaneously effective and as safe as the gluten-free diet. The rationale behind enzyme supplementation therapy as a future treatment option for celiac patients lies in the fact that gluten is only poorly digested by gastrointestinal proteases. Due to incomplete degradation in the gastrointestinal tract, fairly long gluten peptides enter the small-intestinal lumen and come into contact with the mucosal epithelium, and in celiac disease patients this encounter launches deleterious downstream effects. Enzyme supplement therapy using either bacterial or fungal endopeptidases or proteases from germinating cereals has been proposed to promote complete digestion of prolamins and destroy disease-inducing gluten peptides. A major advantage of these glutenases is that they work in the lumen of the small intestine and do not themselves take part in the immunological cascade of events in the lamina propria, thus being unlikely to cause harmful side effects to the host. Studies to test this rationale, e.g. with Aspergillus niger prolyl endoprotease and a combination enzyme product ALV003, are already ongoing. The development of a novel medication for celiac disease is still in its early days, and thus the conventional dietary treatment will hold its place for the time being.

Celiac disease patient IgA antibodies induce endothelial adhesion and cell polarization defects via extracellular transglutaminase 2.

We have recently found that celiac disease patient serum-derived autoantibodies targeted against transglutaminase 2 interfere with several steps of angiogenesis, including endothelial sprouting and migration, though the mechanism involved remained to be fully characterized. This study now investigated the processes underlying the antiangiogenic effects exerted by celiac disease patient antibodies on endothelial cells, with particular regard to the adhesion, migration, and polarization signaling pathway. We observed that celiac IgA reduced endothelial cell numbers by affecting adhesion without increasing apoptosis. Endothelial cells in the presence of celiac IgA showed weak attachment, a high susceptibility to detach from fibronectin, and a disorganized extracellular matrix due to a reduction of protein cross-links. Furthermore, celiac patient IgA led to secretion of active transglutaminase 2 from endothelial cells into the culture supernatants. Additionally, cell surface transglutaminase 2 mediated integrin clustering in the presence of celiac IgA was coupled to augmented expression of ß1-integrin. We also observed that celiac patient IgA-treated endothelial cells had migratory defects and a less polarized phenotype when compared to control groups, and this was associated with the RhoA signaling pathway. These biological effects mediated by celiac IgA on endothelial cells were partially influenced but not completely abolished by R281, an irreversible extracellular transglutaminase 2 enzymatic activity inhibitor. Taken together, our results imply that celiac patient IgA antibodies disturb the extracellular protein cross-linking function of transglutaminase 2, thus altering cell-extracellular matrix interactions and thereby affecting endothelial cell adhesion, polarization, and motility.

A single conformational transglutaminase 2 epitope contributed by three domains is critical for celiac antibody binding and effects.

The multifunctional, protein cross-linking transglutaminase 2 (TG2) is the main autoantigen in celiac disease, an autoimmune disorder with defined etiology. Glutamine-rich gliadin peptides from ingested cereals, after their deamidation by TG2, induce T-lymphocyte activation accompanied by autoantibody production against TG2 in 1-2% of the population. The pathogenic role and exact binding properties of these antibodies to TG2 are still unclear. Here we show that antibodies from different celiac patients target the same conformational TG2 epitope formed by spatially close amino acids of adjacent domains. Glu153 and 154 on the first alpha-helix of the core domain and Arg19 on first alpha-helix of the N-terminal domain determine the celiac epitope that is accessible both in the closed and open conformation of TG2 and dependent on the relative position of these helices. Met659 on the C-terminal domain also can cooperate in antibody binding. This composite epitope is disease-specific, recognized by antibodies derived from celiac tissues and associated with biological effects when passively transferred from celiac mothers into their newborns. These findings suggest that celiac antibodies are produced in a surface-specific way for which certain homology of the central glutamic acid residues of the TG2 epitope with deamidated gliadin peptides could be a structural basis. Monoclonal mouse antibodies with partially overlapping epitope specificity released celiac antibodies from patient tissues and antagonized their harmful effects in cell culture experiments. Such antibodies or similar specific competitors will be useful in further functional studies and in exploring whether interference with celiac antibody actions leads to therapeutic benefits.