Celiac disease: pathogenesis of a model immunogenetic disease

Influence of milk-feeding type and genetic risk of developing coeliac disease on intestinal microbiota of infants: the PROFICEL study

Interactions between environmental factors and predisposing genes could be involved in the development of coeliac disease (CD). This study has assessed whether milk-feeding type and HLA-genotype influence the intestinal microbiota composition of infants with a family history of CD. The study included 164 healthy newborns, with at least one first-degree relative with CD, classified according to their HLA-DQ genotype by PCR-SSP DQB1 and DQA1 typing. Faecal microbiota was analysed by quantitative PCR at 7 days, and at 1 and 4 months of age. Significant interactions between milk-feeding type and HLA-DQ genotype on bacterial numbers were not detected by applying a linear mixed-model analysis for repeated measures. In the whole population, breast-feeding promoted colonization of C. leptum group, B. longum and B. breve, while formula-feeding promoted that of Bacteroides fragilis group, C. coccoides-E. rectale group, E. coli and B. lactis. Moreover, increased numbers of B. fragilis group and Staphylococcus spp., and reduced numbers of Bifidobacterium spp. and B. longum were detected in infants with increased genetic risk of developing CD. Analyses within subgroups of either breast-fed or formula-fed infants indicated that in both cases increased risk of CD was associated with lower numbers of B. longum and/or Bifidobacterium spp. In addition, in breast-fed infants the increased genetic risk of developing CD was associated with increased C. leptum group numbers, while in formula-fed infants it was associated with increased Staphylococcus and B. fragilis group numbers. Overall, milk-feeding type in conjunction with HLA-DQ genotype play a role in establishing infants' gut microbiota; moreover, breast-feeding reduced the genotype-related differences in microbiota composition, which could partly explain the protective role attributed to breast milk in this disorder.

Prevalence of celiac disease in siblings of Iranian patients with celiac disease

CONTEXT

Celiac disease, one of the best-known autoimmune human leukocyte antigen-dependent disorders, has a relatively increased prevalence in first-degree relatives.

OBJECTIVE

To determine the prevalence of celiac disease in siblings of patients with confirmed celiac disease.

METHODS

Siblings of confirmed celiac disease patients in our center were identified and enrolled in this study. Their serum immunoglobulin A and tissue transglutaminase antibody-enzyme-linked immunosorbent assay (anti-tissue transglutaminase, immunoglobulin A, and immunoglobulin G) were measured and multiple endoscopic duodenal biopsy specimens were obtained with parental consensus. Celiac disease was confirmed by observation of characteristic histological changes.

RESULTS

A total of 49 children (male, 29; female, 20; age, 2-16 years) with confirmed celiac disease in a pediatric gastroenterology ward were studied from 1999 to 2006. We found 30 siblings (female, 16) all shared in both parents. The only measurement available was for immunoglobulin A tissue transglutaminase antibody. A duodenal biopsy was performed in all 30 siblings. Clinical findings such as abdominal pain, fatigue, growth retardation and diarrhea were found in 53.3% of the completely studied siblings, and positive serology without histological changes was identified in four cases. Both serology and biopsy (confirmed new cases) were positive in 2 of the 30 siblings.

CONCLUSION

High prevalence of celiac disease among siblings of patients with confirmed celiac disease necessitates serologic screening (and confirmatory biopsy if indicated) in families having celiac disease. It is advantageous to diagnose the disease as soon as possible because early diagnosis and diet intervention may prevent serious complications such as growth retardation, short stature, chronic diarrhea, and malignancy.

Probe-based confocal laser microscopy identifies criteria predictive of active celiac sprue

BACKGROUND

Celiac sprue is an underdiagnosed chronic intestinal inflammatory disease. Probe-based confocal laser microscopy (CLM) is a novel endoscopic technique for in vivo inspection of the intestinal mucosa that has not been evaluated in celiac sprue yet.

AIMS

To develop CLM criteria most predictive of celiac pathology in a prospective pilot study.

METHODS

Twenty-one patients (male n = 5, f = 16, mean age 52 years) with established or suspected celiac sprue, seven of whom had confirmed active disease (Marsh III) and 14 duodenal normal mucosa. CLM images from 91 duodenal sites were assessed. CLM recordings were obtained next to Argon beamer labeled areas. Biopsies were taken from the same spots for precise histological matching. After establishing histology-correlated criteria on one sample per patient, the remaining CLM recordings from the same patients were randomized and blindly evaluated.

RESULTS

Villous atrophy and irregular appearing villi were most predictive of celiac pathology. Although the presence of crypts was diagnostic for celiac pathology, it was only recognized in 26.7% of celiac pathology sites. Using these criteria in the blinded assessment, the overall endoscopist's prediction of celiac sprue was accurate in 89.8% of all biopsy sites in 85.7% of all patients. Preliminary interobserver agreement testing villous atrophy, irregular villi, and crypts was poor (kappa 0.05 to 0.26).

CONCLUSIONS

Probe-based CLM criteria developed in this pilot trial appear promising for the detection of active celiac sprue. Preliminary interobserver variability was high, indicating a learning curve effect. Our criteria need validation in an independent patient population.

Interferon-γ activates transglutaminase 2 via a phosphatidylinositol-3-kinase-dependent pathway: implications for celiac sprue therapy

The mechanism for activation of extracellular transglutaminase 2 (TG2) in the small intestine remains a fundamental mystery in our understanding of celiac sprue pathogenesis. Using the T84 human enterocytic cell line, we show that interferon-γ (IFN-γ), the predominant cytokine secreted by gluten-reactive T cells in the celiac intestine, activates extracellular TG2 in a dose-dependent manner. IFN-γ mediated activation of TG2 requires phosphatidylinositol-3-kinase (PI3K) activity, but is uninfluenced by a number of other kinases reported to be active in T84 cells. Pharmacological inhibition of PI3K in the presence of IFN-γ prevents TG2 activation as well as the previously characterized increase in transepithelial permeability. Our findings therefore establish PI3K as an attractive target for celiac sprue therapy, a possibility that is underscored by the encouraging safety profiles of several PI3K inhibitors undergoing human clinical trials.

Immunomodulatory functions of type I interferons

Interferon-α (IFNα) and IFNβ, collectively known as type I IFNs, are the major effector cytokines of the host immune response against viral infections. However, the production of type I IFNs is also induced in response to bacterial ligands of innate immune receptors and/or bacterial infections, indicating a broader physiological role for these cytokines in host defence and homeostasis than was originally assumed. The main focus of this Review is the underappreciated immunomodulatory functions of type I IFNs in health and disease. We discuss their function in the regulation of innate and adaptive immune responses, the response to bacterial ligands, inflammasome activation, intestinal homeostasis and inflammatory and autoimmune diseases.

Increased bacterial translocation in gluten-sensitive mice is independent of small intestinal paracellular permeability defect

AIM

We investigated whether treatment with gliadin induces a paracellular permeability defect that enhances bacterial translocation to mesenteric lymph nodes (MLN) via resident dendritic cells (DC) expressing TLR-2 or 4 in HCD4/HLA-DQ8 transgenic mice.

METHODS

HLA-DQ8 transgenic mice were sensitized and subsequently gavaged with gliadin, in the presence or absence of AT1001 (paracellular permeability inhibitor). Non-sensitized mice were gavaged with indomethacin (permeability inducer) or rice cereal. CD11c and CD103 (DC markers) and TLR-2 and 4 were investigated by immunostaining. Intestinal permeability was assessed by paracellular flux of (51)Cr-EDTA in Ussing chambers. Bacterial translocation to MLN was performed by plate counting on aerobic and anaerobic conditions.

RESULTS

In gliadin-treated mice, both (51)Cr-EDTA flux in jejunal mucosa and aerobic and anaerobic bacterial counts in MLN were increased (p < 0.05) compared to indomethacin-treated mice and controls. The inhibitor AT1001 normalized (51)Cr-EDTA flux, but had no effect on bacterial translocation in gliadin-treated mice. In addition, changes in mucosal DC marker distribution such as increased (p < 0.05) trans-epithelial CD103(+) cells and reduction (p < 0.05) of CD11c immunostaining were detected in gliadin-treated mice. Moreover, changes in DC markers and TLR-2 or 4 immunophenotypes were not associated.

CONCLUSIONS

Pharmacological restoration of paracellular permeability was not sufficient to prevent bacterial translocation in gluten-sensitive mice. We hypothesize that transcellular mechanisms involving CD103(+)DC and CD11c(+)DC may explain in gluten-sensitive HCD4/HLA-DQ8 transgenic mice the sustained increased bacterial translocation observed in the absence of a significant inflammatory response.

Sensitization to gliadin induces moderate enteropathy and insulitis in nonobese diabetic-DQ8 mice

Celiac disease (CD) is frequently diagnosed in patients with type 1 diabetes (T1D), and T1D patients can exhibit Abs against tissue transglutaminase, the auto-antigen in CD. Thus, gliadin, the trigger in CD, has been suggested to have a role in T1D pathogenesis. The objective of this study was to investigate whether gliadin contributes to enteropathy and insulitis in NOD-DQ8 mice, an animal model that does not spontaneously develop T1D. Gliadin-sensitized NOD-DQ8 mice developed moderate enteropathy, intraepithelial lymphocytosis, and barrier dysfunction, but not insulitis. Administration of anti-CD25 mAbs before gliadin-sensitization induced partial depletion of CD25(+)Foxp3(+) T cells and led to severe insulitis, but did not exacerbate mucosal dysfunction. CD4(+) T cells isolated from pancreatic lymph nodes of mice that developed insulitis showed increased proliferation and proinflammatory cytokines after incubation with gliadin but not with BSA. CD4(+) T cells isolated from nonsensitized controls did not response to gliadin or BSA. In conclusion, gliadin sensitization induced moderate enteropathy in NOD-DQ8 mice. However, insulitis development required gliadin-sensitization and partial systemic depletion of CD25(+)Foxp3(+) T cells. This humanized murine model provides a mechanistic link to explain how the mucosal intolerance to a dietary protein can lead to insulitis in the presence of partial regulatory T cell deficiency.

Effect of hookworm infection on wheat challenge in celiac disease--a randomised double-blinded placebo controlled trial

BACKGROUND AND AIMS

The association between hygiene and prevalence of autoimmune disease has been attributed in part to enteric helminth infection. A pilot study of experimental infection with the hookworm Necator americanus was undertaken among a group of otherwise healthy people with celiac disease to test the potential of the helminth to suppress the immunopathology induced by gluten.

METHODS

In a 21-week, double-blinded, placebo-controlled study, we explored the effects of N. americanus infection in 20 healthy, helminth-naïve adults with celiac disease well controlled by diet. Staged cutaneous inoculations with 10 and 5 infective 3(rd) stage hookworm larvae or placebo were performed at week-0 and -12 respectively. At week-20, a five day oral wheat challenge equivalent to 16 grams of gluten per day was undertaken. Primary outcomes included duodenal Marsh score and quantification of the immunodominant α-gliadin peptide (QE65)-specific systemic interferon-γ-producing cells by ELISpot pre- and post-wheat challenge.

RESULTS

Enteric colonisation with hookworm established in all 10 cases, resulting in transiently painful enteritis in 5. Chronic infection was asymptomatic, with no effect on hemoglobin levels. Although some duodenal eosinophilia was apparent, hookworm-infected mucosa retained a healthy appearance. In both groups, wheat challenge caused deterioration in both primary and several secondary outcomes.

CONCLUSIONS

Experimental N. americanus infection proved to be safe and enabled testing its effect on a range of measures of the human autoimmune response. Infection imposed no obvious benefit on pathology.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00671138.

Nuclear fluorescence serum reactivity on monkey oesophagus: a new antibody for the follow-up of coeliac disease?

We have identified previously a nuclear fluorescence reactivity (NFR) pattern on monkey oesophagus sections exposed to coeliac disease (CD) patients' sera positive for anti-endomysium antibodies (EMA). The aim of the present work was to characterize the NFR, study the time-course of NFR-positive results in relation to gluten withdrawal and evaluate the potential role of NFR in the follow-up of CD. Twenty untreated, 87 treated CD patients and 15 healthy controls were recruited and followed for 12 months. Their sera were incubated on monkey oesophagus sections to evaluate the presence of NFR by indirect immunofluorescence analysis. Duodenal mucosa samples from treated CD patients were challenged with gliadin peptides, and thus the occurrence of NFR in culture supernatants was assessed. The NFR immunoglobulins (Igs) reactivity with the nuclear extract of a human intestinal cell line was investigated. Serum NFR was present in all untreated CD patients, persisted up to 151 ± 37 days from gluten withdrawal and reappeared in treated CD patients under dietary transgressions. Serum NFR was also detected in two healthy controls. In culture supernatants of coeliac intestinal mucosa challenged with gliadin peptides, NFR appeared before EMA. The Igs responsible for NFR were identified as belonging to the IgA2 subclass. The NFR resulted differently from EMA and anti-nuclear antibodies, but reacted with two nuclear antigens of 65 and 49 kDa. A new autoantibody, named NFR related to CD, was described. Furthermore, NFR detection might become a valuable tool in monitoring adherence to a gluten-free diet and identifying slight dietary transgressions.

Frequency distribution of HLA DQ2 and DQ8 in celiac patients and first-degree relatives in Recife, northeastern Brazil

AIMS

The aim of this study was to evaluate the frequencies of the HLA genotypes DQ2 and DQ8 and the alleles A1*05, A1*0201, B1*0201 and B1*0302 in individuals with celiac disease in Recife, northeastern Brazil.

METHODS

HLA DQ2 and DQ8 genotyping was performed for 73 individuals with celiac disease and 126 first-degree relatives with negative transglutaminase serology. The alleles DQA1*05, DQA1*0201, DQB1*02 and DQB1*0302 were identified by sequencing using specific primers and the EU-DQ kit from the Eurospital Laboratory, Trieste, Italy and double-checked by the All Set SPP kit (Dynal).

RESULTS

Among the 73 cases, 50 (68.5%) had the genotype DQ2, 13 (17.8%) had DQ8, 5 (6.8%) had DQ2 and DQ8, and 5 did not have any of these genotypes. Among the 5 negative individuals, four had the B1*02 allele and one did not have any of the alleles studied. B1*02 was the most frequent allele in both groups (94% in the patients and 89% in the control relatives).

CONCLUSIONS

In this study, celiac disease was associated with the genotypes DQ2 and DQ8. DQ2 predominated, but the distribution of the frequencies was different from what has been found in European populations and was closer to what has been found in the Americas. The high frequencies of the HLA genotypes DQ2 and DQ8 that were found in first-degree relatives would make it difficult to use these HLA genotypes for routine diagnosis of celiac disease in this group.

A universal approach to eliminate antigenic properties of alpha-gliadin peptides in celiac disease

Celiac disease is caused by an uncontrolled immune response to gluten, a heterogeneous mixture of wheat storage proteins, including the α-gliadins. It has been shown that α-gliadins harbor several major epitopes involved in the disease pathogenesis. A major step towards elimination of gluten toxicity for celiac disease patients would thus be the elimination of such epitopes from α-gliadins. We have analyzed over 3,000 expressed α-gliadin sequences from 11 bread wheat cultivars to determine whether they encode for peptides potentially involved in celiac disease. All identified epitope variants were synthesized as peptides and tested for binding to the disease-associated HLA-DQ2 and HLA-DQ8 molecules and for recognition by patient-derived α-gliadin specific T cell clones. Several specific naturally occurring amino acid substitutions were identified for each of the α-gliadin derived peptides involved in celiac disease that eliminate the antigenic properties of the epitope variants. Finally, we provide proof of principle at the peptide level that through the systematic introduction of such naturally occurring variations α-gliadins genes can be generated that no longer encode antigenic peptides. This forms a crucial step in the development of strategies to modify gluten genes in wheat so that it becomes safe for celiac disease patients. It also provides the information to design and introduce safe gluten genes in other cereals, which would exhibit improved quality while remaining safe for consumption by celiac disease patients.

Are patients with potential celiac disease really potential? The answer of metabonomics

Celiac disease (CD) is an autoimmune disorder caused by a permanent sensitivity to gluten in genetically susceptible individuals. Accurate diagnosis of CD at an early stage and its treatment with a gluten-free diet (GFD) are important for optimum treatment and prognosis. Recently, by employing a noninvasive metabonomic approach, we have shown that CD has a well-defined metabonomic signature. Here we address potential CD patients, defined as subjects who do not have, and have never had, a jejunal biopsy consistent with clear CD, and yet have immunological abnormalities similar to those found in celiac patients. Sixty-one overt CD patients at diagnosis, 29 patients with potential CD, and 51 control subjects were examined by (1)H NMR of their serum and urine: out of 29 potential CD patients, 24 were classified as CD and 5 as control subjects. Potential CD largely shares the metabonomic signature of overt CD. Most metabolites found to be significantly different between control and CD subjects were also altered in potential CD. Our results demonstrate that metabolic alterations may precede the development of small intestinal villous atrophy and provide a further rationale for early institution of GFD in patients with potential CD, as recently suggested by prospective clinical studies.

Prevention measures and exploratory pharmacological treatments of celiac disease

Increasing prevalence, protean clinical manifestations, and lack of pharmacological therapy make celiac disease (CD) a complex and highly relevant illness in gastroenterology. This chronic inflammatory disorder of the small intestine is caused by the ingestion of gluten containing cereals in genetically susceptible individuals, leading to a variety of gastrointestinal (GI) and non-GI manifestations. Awareness among physicians is growing due to accessible and highly accurate diagnostic and screening methods. Recent evidence suggests a possible rising incidence of CD. Environmental factors such as early life gluten exposure, intestinal infections, short duration of breast-feeding, and changes in intestinal microbiota have been proposed to have a role in CD pathogenesis. Thus, prevention approaches to diminish the rising prevalence of CD are currently being evaluated. Still, the cornerstone treatment of CD remains a strict gluten-free diet. This nutritional regime is demanding, and non-adherence is common because of social isolation, financial issues, or restriction of food diversity. Allowing patients to occasionally consume small amounts of gluten would greatly improve their quality of life. Owing to recent advances in the understanding of the pathogenesis of CD, different targets have been identified and have motivated the development of several experimental therapeutic strategies. The main goal of this review is to discuss the mechanisms that can be exploited therapeutically to prevent or delay CD, disease associations and its complications. Current treatments for complications of CD, including refractory CD and malignancy, are beyond the scope of this review.

Effective shutdown in the expression of celiac disease-related wheat gliadin T-cell epitopes by RNA interference

Celiac disease (CD) is an enteropathy triggered by the ingestion of gluten proteins from wheat and similar proteins from barley and rye. The inflammatory reaction is controlled by T cells that recognize gluten peptides in the context of human leukocyte antigen (HLA) DQ2 or HLA-DQ8 molecules. The only available treatment for the disease is a lifelong gluten-exclusion diet. We have used RNAi to down-regulate the expression of gliadins in bread wheat. A set of hairpin constructs were designed and expressed in the endosperm of bread wheat. The expression of gliadins was strongly down-regulated in the transgenic lines. Total gluten protein was extracted from transgenic lines and tested for ability to stimulate four different T-cell clones derived from the intestinal lesion of CD patients and specific for the DQ2-α-II, DQ2-γ-VII, DQ8-α-I, and DQ8-γ-I epitopes. For five of the transgenic lines, there was a 1.5-2 log reduction in the amount of the DQ2-α-II and DQ2-γ-VII epitopes and at least 1 log reduction in the amount of the DQ8-α-I and DQ8-γ-I epitopes. Furthermore, transgenic lines were also tested with two T-cell lines that are reactive with ω-gliadin epitopes. The total gluten extracts were unable to elicit T-cell responses for three of the transgenic wheat lines, and there were reduced responses for six of the transgenic lines. This work shows that the down-regulation of gliadins by RNAi can be used to obtain wheat lines with very low levels of toxicity for CD patients.

Screening for coeliac disease among Egyptian children

INTRODUCTION

To screen for coeliac disease in Egyptian children with non-endocrinal short stature, refractory iron deficiency anaemia and type 1 diabetes. Also, to evaluate the sensitivity and specificity of different serological tests for diagnosis of coeliac disease (CD).

MATERIAL AND METHODS

The study included 292 patients with clinical risk of CD. Testing for coeliac antibodies was performed, together with upper gastrointestinal endoscopy and small intestinal biopsy.

RESULTS

Eleven patients (44%) among 25 patients with refractory iron deficiency anaemia, 23 patients (34.3%) among 67 patients with non-endocrinal short stature, and 6 patients (3%) among 200 patients with type I diabetes mellitus were diagnosed by jejunal biopsy as having coeliac disease. AGA (IgG) had the highest sensitivity for diagnosing CD (80.0%) followed by the TTG (72.7%) antibody, while ARA had the highest specificity (95.9%) followed by anti-EMA (94.7%).

CONCLUSIONS

Coeliac disease is more common in Egyptian children with refractory iron deficiency anaemia, non-endocrinal short stature and type 1 diabetes than was previously thought; therefore it is mandatory to screen such patients for CD. Serological tests showed fairly good sensitivity and specificity for the diagnosis; however, intestinal biopsy remains the cornerstone for definitive diagnosis of patients with immunological reaction to gluten.

Symptomless celiac disease in type 1 diabetes: 12-year experience in Estonia

BACKGROUND

We aimed to determine the prevalence and characteristics of celiac disease in children with type 1 diabetes in Estonia, a country with a formerly low frequency of both diseases.

METHODS

Altogether, 271 patients with diabetes were studied over 12 years (1995-2006): 122 at diagnosis and 149 patients 0.1-14.8 years after diagnosis. In addition, 73 patients were followed up over 1-6 years. Immunoglobulin A type endomysium and tissue transglutaminase antibodies were determined. Patients with antibodies and/or with celiac-disease-related symptoms were invited for a small-intestinal biopsy.

RESULTS

At the primary screening, celiac disease was histologically confirmed in nine patients (all without symptoms), that is, in 3.3% (95% confidence interval: 1.63-6.42) of type 1 diabetes cases. At follow up, celiac disease was additionally detected in two (2.7%) of 73 diabetic patients, that is, in 0.016 (95% confidence interval: 0-0.072) celiac disease cases per follow-up year.

CONCLUSION

The prevalence of celiac disease among type 1 diabetes patients in Estonia is similar to that in countries with a high incidence of celiac disease and type 1 diabetes. As celiac disease is mostly symptomless, all children with type 1 diabetes, irrespective of their geographic origin, should be regularly screened for celiac disease.

Regulation of major histocompatibility complex class II gene expression, genetic variation and disease

Major histocompatibility complex (MHC) class II molecules are central to adaptive immune responses and maintenance of self-tolerance. Since the early 1970s, the MHC class II region at chromosome 6p21 has been shown to be associated with a remarkable number of autoimmune, inflammatory and infectious diseases. Given that a full explanation for most MHC class II disease associations has not been reached through analysis of structural variation alone, in this review we examine the role of genetic variation in modulating gene expression. We describe the intricate architecture of the MHC class II regulatory system, indicating how its unique characteristics may relate to observed associations with disease. There is evidence that haplotype-specific variation involving proximal promoter sequences can alter the level of gene expression, potentially modifying the emergence and expression of key phenotypic traits. Although much emphasis has been placed on cis-regulatory elements, we also examine the role of more distant enhancer elements together with the evidence of dynamic inter- and intra-chromosomal interactions and epigenetic processes. The role of genetic variation in such mechanisms may hold profound implications for susceptibility to common disease.

Discordância de apresentação da doença celíaca em gêmeos monozigóticos

CONTEXTO: A doença celíaca é uma enteropatia autoimune causada pela sensibilidade ao glúten em indivíduos geneticamente predispostos. Apesar da característica genética da doença, estudos demonstram discordância de 30% na sua apresentação em gêmeos monozigóticos. OBJETIVO: Apresentar dois pares de gêmeos monozigóticos, comprovados por estudos genéticos, discordantes para apresentação da doença celíaca. MÉTODO: Os pacientes foram acompanhados no Serviço de Gastroenterologia Pediátrica do Hospital das Clínicas da Universidade Federal de Minas Gerais desde 1990, sendo submetidos a exames clínicos periódicos, biopsias intestinais e sorologia para anticorpos IgG e IgA antigliadina, determinados pela técnica de ELISA (ensaio imunoenzimático), e anticorpos classe IgA antiendomísio, determinados pela técnica de imunofluorescência indireta. Estudos genéticos foram realizados através da técnica de amplificação por PCR e posterior tipagem de loci de microssatélites do tipo STR (short tandem repeats). RESULTADOS: Em cada par de gêmeos, apenas um apresentou doença celíaca até o momento, mostrando que, apesar do genótipo idêntico, este não foi o único determinante para a expressão da doença. CONCLUSÃO: Outros fatores, ambientais e genéticos, parecem contribuir para determinação da doença.

Prevalence, human leukocyte antigen typing and strategy for screening among Asian first-degree relatives of children with celiac disease

BACKGROUND AND AIM

Data on prevalence, human leukocyte antigen (HLA) typing and small bowel histology among first-degree relatives of subjects with celiac disease (CD) is scarce. This prospective study evaluated the prevalence and role of HLA DQ2/8 testing in screening of first-degree relatives of children with CD.

METHODS

Thirty confirmed children with CD and 91/94 first-degree relatives (parents and siblings) were enrolled. HLA DQ2/8 testing was carried out in all index CD cases. Clinical evaluation with a questionnaire, total serum immunoglobulin A (IgA), human IgA-tissue transglutaminase (IgA-tTGA) and HLA DQ2/8 testing was carried out in all first-degree relatives. Subjects who were positive for IgA-tTGA were recommended endoscopic duodenal biopsy to document histological changes of CD.

RESULTS

Nine first-degree relatives were positive for IgA-tTGA, seven underwent duodenal biopsy and four subjects had Marsh IIIa changes suggestive of CD. The prevalence of histologically confirmed CD in first-degree relatives was 4.4%. The prevalence of potential CD was 9.8%. IgA-tTGA-positive subjects (4/9) were significantly more often symptomatic than IgA-tTGA-negative first-degree relatives (2/82). Twenty-nine (96.6%) index cases of CD and all IgA-tTGA-positive first-degree relatives were positive for HLA DQ2. None of the index CD cases or first-degree relatives were HLA DQ8-positive. A total of 85% of the first-degree relatives were positive for HLA DQ2 and thus at risk of developing CD.

CONCLUSIONS

In this first Asian study on a limited number of families of children with CD, 4.4% of the first-degree relatives had CD. Only 15% of the first-degree relatives were negative for HLA DQ2/DQ8. Initial evaluation with HLA and serology followed by only serial serology in HLA-positive relatives is recommended.

Characterization of IL-17A-producing cells in celiac disease mucosa

Celiac disease (CD) is a gluten-sensitive enteropathy associated with a marked infiltration of the mucosa with IFN-gamma-secreting Th1 cells. Recent studies have shown that a novel subset of T cells characterized by expression of high levels of IL-17A, termed Th17 cells, may be responsible for pathogenic effects previously attributed to Th1 cells. In this study, we characterized the expression of IL-17A-producing cells in CD. By real-time PCR and ELISA, it was shown that expression of IL-17A RNA and protein is more pronounced in active CD biopsy specimens in comparison with inactive CD and normal mucosal biopsy specimens. Flow cytometry confirmed that IL-17A is overproduced in CD mucosa and that CD4(+) and CD4(+)CD8(+) cells were major sources. The majority of IL-17A-producing CD4(+) and CD4(+)CD8(+) cells coexpressed IFN-gamma but not CD161. The addition of a peptic-tryptic digest of gliadin to ex vivo organ cultures of duodenal biopsy specimens taken from inactive CD patients enhanced IL-17A production by both CD4(+) and CD4(+)CD8(+) cells. Because we previously showed that IL-21, a T cell-derived cytokine involved in the control of Th17 cell responses, is overproduced in CD, we next assessed whether IL-17A expression is regulated by IL-21. Blockade of IL-21 activity by a neutralizing IL-21 Ab reduced IL-17A expression in cultures of active CD and peptic-tryptic digest of gliadin-treated CD biopsy specimens. In conclusion, our data show that IL-17A is increased in CD and is produced by cells that also make IFN-gamma.

Preparation and characterization of enzymatically hydrolyzed prolamins from wheat, rye, and barley as references for the immunochemical quantitation of partially hydrolyzed gluten

Celiac disease (CD) is a permanent gastrointestinal disorder characterized by the intolerance to a group of proteins called gluten present in wheat, rye, barley, and possibly oats. The only therapy is a strict lifelong gluten-free diet. The standard method for gluten determination in foods produced for CD patients is the R5-enzyme-linked immunosorbent assay (ELISA) as proposed by the recent Codex Alimentarius Draft Revised Standard. This test is based on the determination of prolamins, the alcohol-soluble proteins of gluten, and is available as a sandwich ELISA for intact proteins and as a competitive ELISA for gluten-derived peptides. While the suitability of the sandwich ELISA including a wheat prolamin (gliadin) reference for calibration has been shown by various studies and a ring test, the competitive ELISA still lacks a convenient reference for the quantitation of gluten peptides in fermented cereal foods (e.g., sourdough products, starch syrup, malt extracts, beer). Therefore, the aim of the present study was to prepare a suitable reference for the quantitation of partially hydrolyzed gluten in fermented wheat, rye, and barley products. The prolamin fractions from barley (hordein) and rye (secalin) were isolated from corresponding flours by means of a modified preparative Osborne fractionation. The prolamin fraction from wheat was obtained as reference gliadin from the Prolamin Working Group. The prolamin fractions were successively digested by pepsin and trypsin or pepsin and chymotrypsin procedures, which have been used for CD-specific toxicity tests on cereal storage proteins for many years. The protein/peptide content (N x 5.7) of the prolamin fractions and digests, which was the basis for the calculation of the gluten content by means of ELISA, varied between 67.1% and 96.0%. The prolamin fractions and enzymatic digests were then tested for their response in both sandwich and competitive assays. Intact prolamins responded similarly in both ELISA showing no important differences between the cereals. In the case of digested proteins, however, the sandwich ELISA was considerably less sensitive than the competitive ELISA. The former provided approximately 40% and the latter 70% of the signal intensity obtained with the intact prolamins. Thus, the combination of the competitive ELISA and the enzymatic digests of prolamin fractions as reference was considered to be an adequate system for the analysis of partially hydrolyzed gluten. The limit of detection using a peptic-tryptic hordein digest as reference was 2.3 microg prolamin equivalent per milliliter, and the limit of quantitation was 6.7 microg prolamin equivalent per milliliter. This system was applied for the determination of gluten equivalents in five commercial beverages based on fermented cereals.

Immunogenicity characterization of two ancient wheat α-gliadin peptides related to coeliac disease

The immunogenic potential of α-gliadin protein from two ancient wheats was studied with reference to coeliac disease. To this aim we investigated Graziella Ra® and Kamut® (the latter is considered an ancient relative of modern durum wheat) in comparison to four durum wheat accessions (Senatore Cappelli, Flaminio, Grazia and Svevo). ELISA and Western Blot analyses - carried out by two monoclonal antibodies raised against the α-gliadin peptides p31-49 (LGQQQPFPQQPYPQPQPF) and p56-75 (LQLQPFPQPQLPYPQPQLPY) containing a core region (underlined) reported to be toxic for coeliac patients - always showed an antibody-antigen positive reaction. For all accessions, an α-gliadin gene has also been cloned and sequenced. Deduced amino acid sequences constantly showed the toxic motifs. In conclusion, we strongly recommend that coeliac patients should avoid consuming Graziella Ra® or Kamut®. In fact their α-gliadin not only is as toxic as one of the other wheat accessions, but also occurs in greater amount, which is in line with the higher level of proteins in ancient wheats when compared to modern varieties.

Pivotal Advance: Bifidobacteria and Gram-negative bacteria differentially influence immune responses in the proinflammatory milieu of celiac disease

CD is a chronic inflammatory disorder of the small intestine that presents in genetically predisposed individuals following gluten consumption. In this study, the effects of Bifidobacterium (Bifidobacterium bifidum IATA-ES2 and Bifidobacterium longum ATCC15707) and Gram-negative bacteria (Bacteroides fragilis DSM2451, Escherichia coli CBL2, and Shigella CBD8 isolated from CD patients), alone and in the presence of CD triggers (gliadins and/or IFN-gamma) on surface marker expression and cytokine production by PBMCs, were determined. These effects were also evaluated in cocultures of PBMCs and Caco-2 cells. The Gram-negative bacteria induced higher secretion of Th1-type proinflammatory cytokines (IL-12 and/or IFN-gamma) than the Bifidobacterium strains. Shigella CBD8 and E. coli CBL2 up-regulated mainly HLA-DR and CD40 expression involved in Th1 activation, and Bifidobacterium strains up-regulated CD83 expression. Specific interactions among the studied bacteria, gliadins, and IFN-gamma, which favored the CD immune features, were also detected. Therefore, intestinal bacteria could be additional factors that regulate the ability of monocytes recruited to the mucosa to respond to gliadins and IFN-gamma in CD patients, influencing the course of the disease.

Aberrant T-lymphocytes in refractory coeliac disease are not strictly confined to a small intestinal intraepithelial localization

BACKGROUND

Refractory coeliac disease (RCD) is characterized by persisting mucosal pathology in spite of a strict gluten free diet (GFD). In RCD type II, phenotypically aberrant (CD7+CD3-CD4/8-cytoplasmicCD3+) T-lymphocytes are present within the intraepitelial lymphocyte (IEL) population in the small intestine, and 50-60% of these patients develops an enteropathy associated T-cell lymphoma (EATL).

AIM

To investigate whether aberrant T-lymphocytes in RCD II can be detected in other parts of the small intestinal mucosa besides the intraepithelial compartment. Additionally, the presence of aberrant T-lymphocytes was analyzed in two RCD II patients that developed atypical skin lesions.

METHODS

Multiparameter flow cytometric immunophenotyping was performed on both IEL and lamina propria lymphocyte (LPL) cell suspensions, isolated from small bowel biopsy specimens of RCD II patients (n = 14), and on cutaneous lymphocytes isolated from skin-lesion biopsy specimens of RCD II patients (n = 2). In addition, immunofluorescence analysis of frozen RCD II derived small intestinal biopsies was performed.

RESULTS

Our results clearly show that aberrant T-lymphocytes may be present in both the IEL and the LPL compartments of RCD II derived small intestinal biopsies. Although the highest percentages are always present in the IEL compartment, aberrant LPL can exceed 20% of total LPL in half the RCD II patients. Interestingly, cutaneous lymphocytes isolated from atypical skin lesions that developed in some RCD II patients showed a similar aberrant immunophenotype as found in the intestinal mucosa.

CONCLUSIONS

In RCD II, the aberrant T-lymphocytes may also reside in the subepithelial layer of the small intestinal mucosa, in the lamina propria, and even in extraintestinal localizations including the skin. Whether this phenomenon represents a passive overflow from the intestinal epithelium or active trafficking towards other anatomical localizations remains to be elucidated. RCD II appears to be a disseminated disease, which may impose the risk of EATL development outside the intestine.

Endocytoscopy for the detection of microstructural features in adult patients with celiac sprue: a prospective, blinded endocytoscopy-conventional histology correlation study

BACKGROUND

Endocytoscopy (EC) is a novel technique that allows magnified live inspection of the intestinal mucosa.

OBJECTIVE

To evaluate EC for the detection of key pathological findings in patients with celiac sprue.

DESIGN

A total of 166 EC recordings were prospectively acquired. Matched videos, images, and biopsy specimens were obtained by duodenal argon beamer labeling of the respective sites.

SETTING

Academic tertiary referral center.

PATIENTS

Forty patients (mean age 51.5 years, 70% women) with established (n = 32) or suspected (n = 8) celiac disease (CD).

INTERVENTIONS

A validated scoring system (Marsh classification) was used to assess disease activity. EC criteria were independently evaluated by 2 gastroenterologists and 1 pathologist.

MAIN OUTCOME MEASUREMENTS

The primary endpoint was to examine EC correlation with conventional CD histology.

RESULTS

Of 166 duodenal biopsy sites, 23% were classified as Marsh III (moderate to severe), 10% as Marsh I (mild), and 67% as Marsh 0 (normal). Using the 450x magnification, we found that identification of crypts was diagnostic for celiac pathology. Four criteria were significant predictors of Marsh III pathology when adjusted by multivariate analysis: low number of villi per visual field (<3; odds ratio [OR] 9.1; 95% CI, 1.3-62.0), confluence of villi (OR 37.1; 95% CI, 1.3-1021.2), irregular epithelial lining (OR 10.9; 95% CI, 2.5-46.7), and inability to delineate loop capillaries (OR 14.9; 95% CI, 3.3-67.0). None was a good predictor of Marsh I pathology.

LIMITATIONS

Single-center experience. No prospective validation of the criteria in an independent patient population.

CONCLUSIONS

EC at 450x magnification accurately identifies mucosal histopathology of advanced CD, but not early morphological changes.

Celiac disease: presentation of 109 children

PURPOSE

The clinical features of patients with celiac disease (CD) are variable. In the present study, clinical and laboratory features of 109 patients with CD were retrospectively evaluated.

MATERIALS AND METHODS

In all cases, diagnosis of CD was made by European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) criteria and clinical and laboratory findings, including hematological and biochemical analyses, immunoglobulin levels, autoantibodies [antinucler antibody (ANA), antidouble stranded DNA (dsDNA), antimitochondrial antibody (AMA), anti-smooth muscle antibody (ASMA), liver kidney antibody (LKM-1), anti thyroid peroxidase (TPO), anti thyroglobulin (Tg)], bone mineral density (BMD), and electroencephalogram were evaluated. The type of CD was recorded.

RESULTS

Of 109 patients with CD, 66 (60.6%) were classical type, 41 (37.6%) were atypical type and 2 (1.8%) were silent type. The mean age was 8.81 +/- 4.63 years and the most common symptom was diarrhea (53.2%) followed by failure to thrive, short stature, and abdominal pain. Paleness (40.4%), underweight (34.8%), and short stature (31.2%) were the most common findings. Iron deficinecy anemia (81.6%), zinc deficiency (64.1%), prolonged prothrombin time (35.8%), and elevated transaminase levels (24.7%) were the most common laboratory findings. Eight percent of patients had at least 1 autoantibody, and 28 of 52 patients had low BMD. Four of 38 patients had abnormalty in electroencephalograms. The prevalance of selective immunoglobulin (Ig) A deficiency was 9.1%. Histocompatibility antigen HLA-DQ and/or DQ8 genotypes were found in 91% of patients. Abdominal distention, iron deficiency, prolonged prothrombine time, hypoalbuminemia, and elevated transaminase levels were more significantly frequent in the classical type than atypical type (p < 0.005).

CONCLUSION

Although classical CD was seen in most patients in the present study, clinical variability of the condition should be kept in mind.

Antibody-mediated blockade of IL-15 reverses the autoimmune intestinal damage in transgenic mice that overexpress IL-15 in enterocytes

Celiac disease (CD) is an autoimmune inflammatory disease with a relatively high prevalence especially in the western hemisphere. A strong genetic component is involved in the pathogenesis of CD with virtually all individuals that develop the disease carrying HLA-DQ alleles that encode specific HLA-DQ2 or HLA-DQ8 heterodimers. Consumption of cereals rich in gluten triggers a chronic intestinal inflammation in genetically susceptible individuals leading to the development of CD. Emerging evidence has implicated a central role for IL-15 in the orchestration and perpetuation of inflammation and tissue destruction in CD. Therefore, IL-15 represents an attractive target for development of new therapies for CD. Transgenic mice that express human IL-15 specifically in enterocytes (T3(b)-hIL-15 Tg mice) develop villous atrophy and severe duodeno-jejunal inflammation with massive accumulation of NK-like CD8(+) lymphocytes in the affected mucosa. We used these mice to demonstrate that blockade of IL-15 signaling with an antibody (TM-beta1) that binds to murine IL-2/IL-15Rbeta (CD122) leads to a reversal of the autoimmune intestinal damage. The present study, along with work of others, provides the rationale to explore IL-15 blockade as a test of the hypothesis that uncontrolled expression of IL-15 is critical in the pathogenesis and maintenance of refractory CD.

Stratifying risk for celiac disease in a large at-risk United States population by using HLA alleles

BACKGROUND & AIMS

Susceptibility to celiac disease (CD) is related to HLA-DQ2 and DQ8 alleles and the heterodimers they encode. The objective of this study was to stratify risk for CD on the basis of HLA-DQ genotype.

METHODS

DNA from 10,191 subjects who are at risk for CD was analyzed for HLA-DQ haplotypes. Individuals with CD were identified as those who tested positive for anti-endomysial immunoglobulin A (EMA+) in an immunofluorescence assay.

RESULTS

Samples homozygous for DQ2.5 (HLA-DQA1 05-DQB1 02) or DQ2.2/DQ2.5 (HLA-DQA1 05-DQB1 02 and HLA-DQA1 0201-DQB1 02) comprised 5.38% of the total; 28.28% of these were EMA+ (95% confidence interval [CI], 24.55-32.26). Of the samples that were DQ2.5 heterozygous (HLA-DQA1 05-DQB1 02); 9.09% were EMA+ (95% CI, 7.82-10.51). Among samples in which HLA-DQ8 (HLA-DQA1 03-DQB1 0302) was detected, 8.42% of homozygotes (95% CI, 3.71-15.92) and 2.11% of heterozygotes (95% CI, 1.43-3.00) were EMA+. Samples with DQ2.2/DQ8 or DQ2.5/DQ8 comprised 5.08% of the total, and 11.78% of these were EMA+ (95% CI, 9.13-14.87). HLA-DQ2 and HLA-DQ8 were absent in 4283 samples (42.03% of the total); 0.16% of these samples were EMA+ (95% CI, 0.07-0.34).

CONCLUSIONS

High-resolution, sequence-specific oligonucleotide probe typing with 35 DQA1-specific and 37 DQB1-specific probes of DNA from more than 10,000 subjects was used to stratify risk of CD in an at-risk U.S. population. DQ2 homozygosity (DQ2.5/DQ2.2+2.5) increased risk for CD, estimated by the rate of EMA positivity, compared with the entire sample population and other DQ genotypes. These data suggest a quantitative relationship between the type/proportion of DQ heterodimers and the risk of CD and identify potential immunotherapeutic targets.

Transglutaminases in inflammation and fibrosis of the gastrointestinal tract and the liver

Transglutaminases are a family of eight currently known calcium-dependent enzymes that catalyze the cross-linking or deamidation of proteins. They are involved in important biological processes such as wound healing, tissue repair, fibrogenesis, apoptosis, inflammation and cell-cycle control. Therefore, they play important roles in the pathomechanisms of autoimmune, inflammatory and degenerative diseases, many of which affect the gastrointestinal system. Transglutaminase 2 is prominent, since it is central to the pathogenesis of celiac disease, and modulates inflammation and fibrosis in inflammatory bowel and chronic liver diseases. This review highlights our present understanding of transglutaminase function in gastrointestinal and liver diseases and therapeutic strategies that target transglutaminase activities.

Host responses to intestinal microbial antigens in gluten-sensitive mice

BACKGROUND AND AIMS

Excessive uptake of commensal bacterial antigens through a permeable intestinal barrier may influence host responses to specific antigen in a genetically predisposed host. The aim of this study was to investigate whether intestinal barrier dysfunction induced by indomethacin treatment affects the host response to intestinal microbiota in gluten-sensitized HLA-DQ8/HCD4 mice.

METHODOLOGY/PRINCIPAL FINDINGS

HLA-DQ8/HCD4 mice were sensitized with gluten, and gavaged with indomethacin plus gluten. Intestinal permeability was assessed by Ussing chamber; epithelial cell (EC) ultra-structure by electron microscopy; RNA expression of genes coding for junctional proteins by Q-real-time PCR; immune response by in-vitro antigen-specific T-cell proliferation and cytokine analysis by cytometric bead array; intestinal microbiota by fluorescence in situ hybridization and analysis of systemic antibodies against intestinal microbiota by surface staining of live bacteria with serum followed by FACS analysis. Indomethacin led to a more pronounced increase in intestinal permeability in gluten-sensitized mice. These changes were accompanied by severe EC damage, decreased E-cadherin RNA level, elevated IFN-gamma in splenocyte culture supernatant, and production of significant IgM antibody against intestinal microbiota.

CONCLUSION

Indomethacin potentiates barrier dysfunction and EC injury induced by gluten, affects systemic IFN-gamma production and the host response to intestinal microbiota antigens in HLA-DQ8/HCD4 mice. The results suggest that environmental factors that alter the intestinal barrier may predispose individuals to an increased susceptibility to gluten through a bystander immune activation to intestinal microbiota.

Emerging analytical methods to determine gluten markers in processed foods--method development in support of standard setting

The availability of analytical methods to detect and determine levels of markers of priority allergens in foods is of the utmost importance to support standard setting initiatives, the development of compliance and enforcement activities, as well as to provide guidance to industry on implementation of quality control practices, ensuring the effectiveness of allergen-related sanitation techniques. This paper describes the development and implementation of a mass-spectrometry-based technique to determine markers for individual sources of gluten in beer products. This methodology was shown to answer the requirements of Health Canada’s proposed labeling standard for individual gluten source declaration, in order to achieve its policy objectives (i.e., protection of sensitive consumers, while promoting choice). Minimal sample work-up was required and the results obtained by ELISA were further complemented using the LC-MS/MS method. This paper aims to demonstrate the feasibility of alternative techniques to ELISA-based methodologies to determine allergen and gluten markers in food.

Induction of antigen-specific tolerance by oral administration of Lactococcus lactis delivered immunodominant DQ8-restricted gliadin peptide in sensitized nonobese diabetic Abo Dq8 transgenic mice

Active delivery of recombinant autoantigens or allergens at the intestinal mucosa by genetically modified Lactococcus lactis (LL) provides a novel therapeutic approach for the induction of tolerance. Celiac disease is associated with either HLA-DQ2- or HLA-DQ8-restricted responses to specific antigenic epitopes of gliadin, and may be treated by induction of Ag-specific tolerance. We investigated whether oral administration of LL-delivered DQ8-specific gliadin epitope induces Ag-specific tolerance. LL was engineered to secrete a deamidated DQ8 gliadin epitope (LL-eDQ8d) and the induction of Ag-specific tolerance was studied in NOD AB degrees DQ8 transgenic mice. Tolerance was assessed by delayed-type hypersensitivity reaction, cytokine measurements, eDQ8d-specific proliferation, and regulatory T cell analysis. Oral administration of LL-eDQ8d induced suppression of local and systemic DQ8-restricted T cell responses in NOD AB degrees DQ8 transgenic mice. Treatment resulted in an Ag-specific decrease of the proliferative capacity of inguinal lymph node (ILN) cells and lamina propria cells. Production of IL-10 and TGF-beta and a significant induction of Foxp3(+) regulatory T cells were associated with the eDQ8d-specific suppression induced by LL-eDQ8d. These data provide support for the development of effective therapeutic approaches for gluten-sensitive disorders using orally administered Ag-secreting LL. Such treatments may be effective even in the setting of established hypersensitivity.

A food-grade enzyme preparation with modest gluten detoxification properties

BACKGROUND AND AIMS

Celiac sprue is a life-long disease characterized by an intestinal inflammatory response to dietary gluten. A gluten-free diet is an effective treatment for most patients, but accidental ingestion of gluten is common, leading to incomplete recovery or relapse. Food-grade proteases capable of detoxifying moderate quantities of dietary gluten could mitigate this problem.

METHODS

We evaluated the gluten detoxification properties of two food-grade enzymes, aspergillopepsin (ASP) from Aspergillus niger and dipeptidyl peptidase IV (DPPIV) from Aspergillus oryzae. The ability of each enzyme to hydrolyze gluten was tested against synthetic gluten peptides, a recombinant gluten protein, and simulated gastric digests of whole gluten and whole-wheat bread. Reaction products were analyzed by mass spectrometry, HPLC, ELISA with a monoclonal antibody that recognizes an immunodominant gluten epitope, and a T cell proliferation assay.

RESULTS

ASP markedly enhanced gluten digestion relative to pepsin, and cleaved recombinant alpha2-gliadin at multiple sites in a non-specific manner. When used alone, neither ASP nor DPPIV efficiently cleaved synthetic immunotoxic gluten peptides. This lack of specificity for gluten was especially evident in the presence of casein, a competing dietary protein. However, supplementation of ASP with DPPIV enabled detoxification of moderate amounts of gluten in the presence of excess casein and in whole-wheat bread. ASP was also effective at enhancing the gluten-detoxifying efficacy of cysteine endoprotease EP-B2 under simulated gastric conditions.

CONCLUSIONS

Clinical studies are warranted to evaluate whether a fixed dose ratio combination of ASP and DPPIV can provide near-term relief for celiac patients suffering from inadvertent gluten exposure. Due to its markedly greater hydrolytic activity against gluten than endogenous pepsin, food-grade ASP may also augment the activity of therapeutically relevant doses of glutenases such as EP-B2 and certain prolyl endopeptidases.

Differential ferritin expression is associated with iron deficiency in coeliac disease

BACKGROUND

Sixty percent of people with coeliac disease (CD) are iron deficient. Many, however, remain iron replete despite the disease.

AIMS

(i) To characterize the changes in duodenal iron transport proteins in CD with and without iron deficiency. (ii) To examine if iron-activated gut lymphocytes can inhibit iron export in an enterocyte cell model.

METHODS

Endoscopic duodenal biopsies were collected from patients with normal duodenum with and without iron deficiency anaemia and untreated CD sufferers with iron deficiency (n=10 each group). mRNA expression of iron transport proteins was determined by quantitative real time PCR. Protein localization and expression was determined from histology sections in patients with normal duodenum (n=20), and patients with untreated CD with and without iron deficiency (n=20). In addition, CaCo2 cells were cocultured with iron-activated lymphocytes 55Fe was used to determine the effect on CaCo2 cell iron transport.

RESULTS

The expression of divalent metal transporter 1 and ferroportin was increased in CD with or without iron deficiency. Ferritin expression was increased in CD but only in those with associated iron deficiency. TNF-alpha produced by activated lymphocytes inhibited iron export from CaCo2 cells.

CONCLUSION

Increased enterocyte ferritin expression may promote iron deficiency in CD and this effect seems to be dependent upon TNF-alpha expression in gut lymphocytes.

Increased FOXP3 expression in small-bowel mucosa of children with coeliac disease and type I diabetes mellitus

OBJECTIVE

To determine whether the expression of FOXP3 is changed in small-bowel mucosa in coeliac disease (CD).

MATERIAL AND METHODS

The study comprised 52 patients (mean age 8.01+/-6.14 years) who had undergone small-bowel biopsies. CD only was diagnosed in 16 patients, and CD with type I diabetes mellitus (T1D) in 7. These 23 patients and 4 others without CD had partial or subtotal villous atrophy (PVA, SVA). Twenty-five persons without CD had normal mucosa. The transcription level of the FOXP3 gene (Hs00203958_m1) was evaluated in biopsy samples (small bowel) using TaqMan gene expression assays. FOXP3 protein in mucosal cells was evaluated with mouse anti-human FOXP3 antibodies and CD25(+), and CD4(+) T cells were evaluated by mouse monoclonal antibodies.

RESULTS

Expression of FOXP3 mRNA was higher in both PVA and SVA compared to normal mucosa (p=0.007). Patients with CD and T1D had higher expression of FOXP3 mRNA than patients with CD alone (p=0.02). The number of FOXP3(+) cells in intestinal mucosa was higher in patients with CD, especially those with coexisting T1D, than in those with normal mucosa (p=0.01). The results of double staining showed that, among all positive cells, FOXP3 expression alone was revealed in 25.6% of the cells, CD25 positivity in 18% and both markers simultaneously were found in 56.5% of lymphocytes (p=0.03). Double staining for CD4 and FOXP3 showed that 87.5% of cells were CD4(+), 2.8% were FOXP3(+) and 9.7% of cells simultaneously expressed the CD4 and FOXP3 markers.

CONCLUSIONS

A more pronounced expression of FOXP3 mRNA and also the number of FOXP3(+) cells (with simultaneous expression of CD25 and CD4 markers) were found in the small-bowel biopsy specimens obtained from children with CD, particularly those with coexisting T1D, compared with the FOXP3 expression in normal mucosa.

Complete recovery of intestinal mucosa occurs very rarely in adult coeliac patients despite adherence to gluten-free diet

BACKGROUND

Expected benefits of gluten-free diet (GFD) in coeliac patients include healing of small intestinal mucosa, but it remains unclear to what extent this benefit is achieved in adults.

AIM

To assess factors affecting histological outcome of GFD in a large cohort of adult coeliac patients.

METHODS

We extracted information on 465 consecutive coeliac patients studied before and during GFD.

RESULTS

Duodenal biopsies at diagnosis were classified as Marsh I in 11, II in 25 and III in 429 cases. After a median 16 months GFD, 38 (8%) patients had histological 'normalization', 300 (65%) had 'remission' with persistent intraepithelial lymphocytosis, 121(26%) had 'no change' and 6 (1%) had 'deterioration'. Coeliac disease related serology was negative in 83% of patients with Marsh III lesion during GFD. Male gender and adherence to GFD were independently associated with histological 'normalization' and 'remission'. Persistence of intraepithelial lymphocytosis was not associated with human lymphocyte antigen gene dose or with Helicobacter pylori infection.

CONCLUSIONS

Complete normalization of duodenal lesions is exceptionally rare in adult coeliac patients despite adherence to GFD, symptoms disappearance and negative CD related serology. Control biopsies are mandatory to identify lack of response to gluten-free diet.

Regulatory lymphocytes and intestinal inflammation

The immune system is pivotal in mediating the interactions between host and microbiota that shape the intestinal environment. Intestinal homeostasis arises from a highly dynamic balance between host protective immunity and regulatory mechanisms. This regulation is achieved by a number of cell populations acting through a set of shared regulatory pathways. In this review, we summarize the main lymphocyte subsets controlling immune responsiveness in the gut and their mechanisms of control, which involve maintenance of intestinal barrier function and suppression of chronic inflammation. CD4(+)Foxp3(+) T cells play a nonredundant role in the maintenance of intestinal homeostasis through IL-10- and TGF-beta-dependent mechanisms. Their activity is complemented by other T and B lymphocytes. Because breakdown in immune regulatory networks in the intestine leads to chronic inflammatory diseases of the gut, such as inflammatory bowel disease and celiac disease, regulatory lymphocytes are an attractive target for therapies of intestinal inflammation.

Coeliac disease

Coeliac disease is a chronic inflammatory disorder of the small bowel induced in genetically susceptible people by the irritant gluten and possibly other environmental cofactors. The disorder is characterised by a diverse clinical heterogeneity that ranges from asymptomatic to severely symptomatic, and it manifests with frank malabsorption, an increased morbidity attributable to the frequent association with autoimmune disorders and increased mortality resulting from the emergence of T-cell clonal proliferations that predispose the patient to enteropathy-type T-cell lymphoma. Our understanding of the molecular basis for this disorder has improved and enabled the identification of targets for new therapies, although a strict gluten-free diet remains the mainstay of safe and effective treatment. In this Seminar we critically reassess the clinical and diagnostic aspects of this disease and new perspectives in its pathogenesis and treatment.

Impact of mass screening for gluten-sensitive enteropathy in working population

AIM: To assess: (1) frequency and clinical relevance of gluten sensitive enteropathy (GSE) detected by serology in a mass screening program; (2) sensitivity of antitransglutaminase (tTGA) and antiendomysium antibodies (EmA); and (3) adherence to gluten-free diet (GFD) and follow-up.

METHODS: One thousand, eight hundred and sixty-eight subjects recruited from an occupational health department underwent analysis for tTGA and EmA and, if positive, duodenal biopsy, DQ2/DQ8 genotyping, clinical feature recording, blood tests, and densitometry were performed. Since > 98% of individuals had tTGA < 2 U/mL, this value was established as the cut-off limit of normality and was considered positive when confirmed twice in the same sample. Adherence to a GFD and follow up were registered.

RESULTS: Twenty-six (1.39%) subjects had positive tTGA and/or EmA, and 21 underwent biopsy: six Marsh III (one IIIa, four IIIb, one IIIc), nine Marsh I and six Marsh 0 (frequency of GSE 1:125). The sensitivity of EmA for GSE was 46.6% (11.1% for Marsh I, 100% for Marsh III), while for tTGA, it was 93.3% (88.8% for Marsh I, 100% for Marsh III). All 15 patients with abnormal histology had clinical features related to GSE. Marsh I and III subjects had more abdominal pain than Marsh 0 (P = 0.029), and a similar trend was observed for distension and diarrhea. No differences in the percentage of osteopenia were found between Marsh I and III (P = 0.608). Adherence to follow-up was 69.2%. Of 15 GSE patients, 66.7% followed a GFD with 80% responding to it.

CONCLUSION: GSE in the general population is frequent and clinically relevant, irrespective of histological severity. tTGA is the marker of choice. Mass screening programs are useful in identifying patients who can benefit from GFD and follow-up.