Gluten-free diet, chromosomal abnormalities, and cancer risk in coeliac disease

Glutathione S-transferase gene polymorphisms in celiac disease and their correlation with genomic instability phenotype

BACKGROUND AND OBJECTIVE

Genomic instability and reduced glutathione S-transferase (GST) activity have been identified as potential risk factors for malignant complications in celiac disease (CD). In this study, we assessed the possible influence of GST polymorphisms on genome instability phenotypes in a genetically characterised group of celiac patients from previous studies.

METHODS

The deletion polymorphisms in GSTM1 and GSTT1 genes and the single-nucleotide polymorphism GSTP1 c.313A>G were genotyped using PCR in a set of 20 untreated adult patients with a known genomic instability phenotype and 69 age- and sex-matched healthy individuals.

RESULTS

The frequencies of variant genotypes in patients were GSTM1-null (30%), GSTT1-null (5%), GSTP1-AG (60%) and GSTP1-GG (15%), and they showed no differences from controls. No significant differences were found in the genotype distribution based on telomere length. Cases with GSTM1-null genotype (83%) and microsatellite stability were more frequent than those with genomic instability. Moreover, carriers of GSTP1-variant genotype (73%) and stable phenotype were significantly increased compared to unstable patients (27%) (P=0.031). No differences were found according to the clinical-pathological characteristics of celiac cases.

CONCLUSIONS

No association between GST polymorphic variants and celiac-associated genomic instability was proven in our cohort. Future studies should explore the usefulness of other biomarkers to distinguish celiac patients who are susceptible to cancer development.

Lymphocytic disorders of the gastrointestinal tract: a review for the practicing pathologist

Increased numbers of intraepithelial lymphocytes (lymphocytosis) can be found in the esophagus, stomach, small intestine, and colon in a variety of clinical circumstances. This review, directed at practicing pathologists, portrays the normal resident lymphocyte population in the mucosa of each segment of the digestive tract and discusses the different situations that may result in quantitative or qualitative alterations of intraepithelial lymphocytes. Esophageal lymphocytosis has not been fully characterized and its clinical significance, if any, awaits definition. Thus, this diagnosis is presently discouraged. In the stomach, it is particularly important to exclude Helicobacter pylori infection and celiac sprue before diagnosing lymphocytic gastritis. Duodenal lymphocytic infiltrates, inextricably tied with alterations of the villous architecture of the mucosa, are often caused by gluten sensitivity. However, similar morphologic changes may be caused by a vast array of other conditions that must be carefully considered and excluded. Lymphocytic and collagenous colitis are most often unexplained, but their frequent association with autoimmune conditions or certain medications deserve a thorough investigation in each case. Using a combination of histologic and clinical clues, a cause for the intraepithelial lymphocytic infiltration can be identified in many instances. As some of the associated conditions are amenable to effective treatment, the importance of diligently seeking such associations before resorting to a diagnosis of primary lymphocytosis is emphasized.

Celiac disease: from oral tolerance to intestinal inflammation, autoimmunity and lymphomagenesis

Celiac disease is a multifactorial disorder and provides a privileged model to decipher how the interplay between environmental and genetic factors can alter mucosal tolerance to a food antigen, lead to chronic intestinal inflammation, and ultimately promote T-cell lymphomagenesis. Here we summarize how HLA-DQ2/8 molecules, the main genetic risk factor for this disease can orchestrate a CD4(+) T-cell adaptive immune response against gluten, and discuss recent data which shed light on the innate and adaptive immune stimuli that collaborate to induce a proinflammatory TH1 response, a massive expansion of intraepithelial lymphocytes, and a cytolytic attack of the epithelium. The intestinal immune response driven in genetically predisposed patients by chronic exposure to gluten emerges as the pathological counterpart of normal acute intestinal responses to intracellular pathogens.

Analysis of genomic instability in adult-onset celiac disease patients by microsatellite instability and loss of heterozygosis

BACKGROUND AND AIMS

Malignant complications of celiac disease (CD) include carcinomas and lymphomas. The genetic basis behind cancer development in CD is not known, but acquisition of genetic abnormalities and genomic instability has been involved. The aim of this study was to explore molecular characteristics of genomic instability in CD patients by analyzing microsatellite instability (MSI) and loss of heterozygosis (LOH) with carefully selected microsatellites.

METHODS

We genotyped small bowel biopsies and peripheral blood samples from 20 untreated CD patients using five microsatellites related to MMR genes (panel A), and five repeats associated with tumor suppressor genes, chromosome instability, inflammation, and cancer (panel B).

RESULTS

Genomic instability was found in seven out of 20 (35%) cases at: D5S107, D18S58, GSTP, TP53 or DCC, being TP53 the most frequently affected (five out of seven cases; 71%). Microsatellite alterations were significantly found using panel B markers (P=0.04). No cases with high frequency of MSI and replication error phenotype were detected. Only one case displayed MSI-L alone. Three patients exhibited LOH and three other cases showed LOH with low level of MSI, being classified as having chromosome instability phenotype.

CONCLUSION

Two novel observations were found in this study: first, the finding that non-neoplastic cells from a group of untreated CD patients present genomic instability at nucleotide level; and second, the advantage to use carefully selected microsatellites to identify celiac patients with molecular instability. Our data support the existence of chromosome instability phenotype in CD, suggesting that stable and unstable patients are genomically distinct subtypes that may follow a different evolution.

Compliance with gluten-free diet in children with coeliac disease

OBJECTIVES

Coeliac disease (CD) is a lifelong disorder with gluten-induced manifestations in different organs. Gluten-free diet (GFD) is required to achieve remission and prevent complications; however, study reports on GFD growth effect are not consistent.

METHODS

Compliance with GFD was estimated according to current body mass and height; presence of anaemia and other signs and symptoms; and attitude toward GFD.

RESULTS

Seventy-one patients with CD (mean age = 12 years; mean age after CD diagnosis = 9 years) were examined and their blood sampled for determination of endomysial antibodies (EMA), haemoglobin, and red blood cell count. Questionnaire analysis revealed 42 (59.1%; 4 EMA positive) patients to be on strict GFD, 19 (26.8%; 5 EMA positive) were taking small amounts of gluten, and 10 (14.1%; all EMA positive) were not on a diet at all. The patients on strict GFD had greatest body height, yet the difference was not significant. These patients also had a higher mean body mass (P = 0.05) and significantly higher mean haemoglobin and mean cell haemoglobin levels (P = 0.05 and P < 0.05, respectively). Apart from chronic fatigue in patients on partial diet (P = 0.05), patient groups did not differ significantly in the frequency of symptoms. Anaemia and delayed puberty were recorded only in noncompliers (P < 0.01 and P < 0.05, respectively). Noncompliers often found the specific diet to pose a major life burden (P < 0.01) and did not visit a gastroenterologist on a regular basis (P < 0.01).

CONCLUSIONS

Almost half of the coeliac patients were likely to abandon GFD without experiencing major symptoms, thus increasing the risk for developing complications later in life. An active attitude is required in the follow-up of patients with CD.

Celiac disease screening by immunochromatographic visual assays: results of a multicenter study

OBJECTIVE

To assay the efficiency for celiac disease (CD) screening of 2 immunochromatographic visual stick assays based on human recombinant tissue transglutaminase (tTG). One was the antitissue transglutaminase antibodies (AtTGA) stick for IgA/G antibodies to tTG detection, the other was the AtTGA/antigliadin antibodies (AGA) stick for IgA antibodies for tTG and/or gliadins.

PATIENTS AND METHODS

In a prospective multicenter study, 4 pediatric gastroenterology units from Spain and 2 from Latin America enrolled 72 control children with a normal small bowel mucosa and 113 untreated patients with CD with Marsh type 3 lesions.

RESULTS

Evaluation of results by the gastroenterologists and by 2 independent observers at the coordination center showed a remarkably low interobserver variability. For the AtTGA stick, sensitivity was 96.5% and specificity was 98.6%. The AtTGA/AGA stick displayed a sensitivity of 94.5% and a specificity of 98.6% for AtTGA and a sensitivity of 63.1% and a specificity of 95.2% for AGA. The highest efficiency and positive likelihood ratio was obtained for the AtTGA stick, higher than for IgA AtTGA by enzyme-linked immunosorbent assay. One additional advantage was that previous investigation of total serum IgA levels could be eluded. The IgA AtTGA/AGA stick, with an efficiency of 95.1%, compared with 89.2% when the combined results of the 2 enzyme-linked immunosorbent assays were considered, turned out to be an excellent diagnostic tool for infants with no IgA deficiency.

CONCLUSION

These 2 assays are extremely efficient for CD screening, by combining a high diagnostic accuracy with the simplicity and rapidity of visual methods.

Celiac disease: current concepts in diagnosis and treatment

Celiac disease is a complex autoimmune enteropathy that affects the small bowel in genetically predisposed individuals. It is thought that celiac disease is the result of an inappropriate T cell-mediated immune response against ingested gluten protein. The characteristic lesion of the small intestinal mucosa includes loss of absorptive villi and infiltration of the lamina propria with inflammatory cells. The clinical presentation of celiac disease varies greatly depending on patient's age, duration and extent of the disease, and the presence of extraintestinal manifestations. Unfortunately, most patients with celiac disease have either silent or atypical presentations, thus escaping diagnosis for several years. Medical nutrition therapy with lifelong adherence to a strict gluten-free diet is the only accepted treatment of celiac disease. Individuals at risk for this entity should undergo appropriate serologic testing, but there is no evidence to support mass screening.

Malignant complications of coeliac disease

Patients with coeliac disease (CD), particularly those who are undiagnosed or do not adhere to a strict gluten free diet (GFD), are prone to develop complications. Malignant complications are the most serious and should be suspected when expected responses to GFD are not achieved or sustained. Lymphomas, mostly T-cell type, and other malignant tumours, particularly carcinoma of the small bowel, less frequently of stomach and oesophagus, are associated with CD. Loss of response to a gluten free diet (refractory coeliac disease) and ulcerative jejunitis are two recently described complications of CD that may progress to an Enteropathy-Associated T-cell Lymphoma (EATL). Coeliac disease-related lymphoma most often appears at extra-nodal sites, essentially the small bowel, although one have to realise that T-cell lymphomas arising in sites outside the small bowel could be related to coeliac disease. Workup of an EATL must include immunehistology and if necessary T-cell flow cytometry and T-cell rearrangement. Adequate imaging with CT and PET-scanning is mandatory.