Aaron Lerner

Immunological diagnosis of childhood coeliac disease: comparison between antigliadin, antireticulin and antiendomysial antibodies.

The immunological markers proposed to supplement intestinal biopsy for the diagnosis of coeliac disease are antigliadin, antireticulin and antiendomysial antibodies. These antibodies have been studied separately or compared as pairs, but no prospective comparison of all three antibodies in childhood coeliac disease exists. Thirty‐four confirmed coeliacs were compared with nine non‐coeliacs with pathological small intestines, and 32 children with a normal intestinal histology. Sera were examined for IgG‐ and IgA‐antigliadin antibodies (AGA) by ELISA, and for IgA‐antireticulin antibodies (ARA) and IgA endomysial antibodies (EMA) by indirect immunofluorescence. In active coeliac disease, IgA‐EMA was the most sensitive (97%), while IgA‐AGA the least sensitive antibody (52%). The specificity of IgA‐AGA, IgG‐AGA, IgA‐ARA, IgA‐EMA was 95%, 92%, 100% and 98%, respectively. Positive predicted values of ARA and EMA were comparable (97‐100%), while EMA had the highest negative predicted value (98%). Compared with IgG‐AGA, IgA‐EMA titres better reflected variations in dietary gluten, and correlated best with intestinal pathology. Compared with AGA and ARA sensitivity, specificity and predictive values, EMA is the most reliable serological marker for the diagnosis of coeliac disease. It reflects dietary changes in gluten and correlates best with intestinal histopathology. Therefore, it should be considered the best of the three serological tests available for childhood coeliac disease.

Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease.

The incidence of autoimmune diseases is increasing along with the expansion of industrial food processing and food additive consumption. The intestinal epithelial barrier, with its intercellular tight junction, controls the equilibrium between tolerance and immunity to non-self-antigens. As a result, particular attention is being placed on the role of tight junction dysfunction in the pathogenesis of AD. Tight junction leakage is enhanced by many luminal components, commonly used industrial food additives being some of them. Glucose, salt, emulsifiers, organic solvents, gluten, microbial transglutaminase, and nanoparticles are extensively and increasingly used by the food industry, claim the manufacturers, to improve the qualities of food. However, all of the aforementioned additives increase intestinal permeability by breaching the integrity of tight junction paracellular transfer. In fact, tight junction dysfunction is common in multiple autoimmune diseases and the central part played by the tight junction in autoimmune diseases pathogenesis is extensively described. It is hypothesized that commonly used industrial food additives abrogate human epithelial barrier function, thus, increasing intestinal permeability through the opened tight junction, resulting in entry of foreign immunogenic antigens and activation of the autoimmune cascade. Future research on food additives exposure-intestinal permeability-autoimmunity interplay will enhance our knowledge of the common mechanisms associated with autoimmune progression.

The use of a single serological marker underestimates the prevalence of celiac disease in Israel: a study of blood donors.

OBJECTIVES:Recent studies suggest that celiac disease was previously underdiagnosed. To find out whether antiendomysial antibodies underestimate the prevalence of celiac disease, we elected to use a strategy combining multiple serological markers to explore the prevalence of celiac disease in Israel and the usefulness of the various antibodies in screening for celiac disease.METHODS:Serum samples from 1571 healthy blood donors were tested. A small intestinal biopsy was offered to all patients who tested positive for either human tissue transglutaminase antibodies, an ELISA kit based on antiendomysium (EMA-ELISA), immunoglobulin A antigliadin verified by antiendomysial immunofluorescence antibodies, and to patients who were IgA deficient with elevated antigliadin IgG.RESULTS:A total of 59 subjects (3.8% of study population) were offered an intestinal biopsy based on serological findings, and 30 of 59 patients agreed to undergo intestinal biopsy (1.9% of study population). Celiac disease was diagnosed in 10 patients, establishing a prevalence of at least 1:157 in the general population (0.6%, CI = 0.3–1.1%). Using any serological marker alone would have underestimated the prevalence of celiac disease, as it was diagnosed in only two patients who tested positive for endomysial immunofluorescence antibodies (prevalence of 1:786, 0.1%, CI = 0.02–0.5%), six patients positive for tissue transglutaminase (prevalence of 1:262, 0.4%, CI = 0.1–0.9%), and seven patients positive for ELISA-EMA (prevalence of 1:224, 0.45%, CI = 0.2–0.9%).CONCLUSIONS:The prevalence of celiac disease in Israel is at least 1:157 in the general population, confirming its underdiagnosis in previous studies. The disparity between the various serological markers suggest that the use of one serological marker is insufficient for establishing the true prevalence of celiac disease.

Tissue transglutaminase--the key player in celiac disease: a review.

Gluten-sensitive enteropathy, otherwise known as celiac sprue, is characterized by an abnormal proximal small intestinal mucosa arising as a result of an inappropriate inflammatory response to ingested gluten antigens present in wheat in genetically susceptible individuals. This immune response is directed to a 33-mer peptide of the alpha gliadin component of gluten. The generation of an epitope for the recognition by CD4+ T cells requires deamination of the protein by tissue transglutaminase (tTG). Moreover, IgA anti tTG is highly sensitive and is specific serologic marker (95-99%) of celiac disease. They can be easily determined quantitatively, by ELISA of an accurate and relatively inexpensive technique. Therefore, tTG can be used as the first line diagnostic test in the work-up of celiac disease, as well as for screening purposes. Finally, tTG may contribute to future strategies in treating celiac disease either by producing nontoxic wheat or by generating oral vaccination that can prevent the disease.

New therapeutic strategies for celiac disease

Celiac disease is an autoimmune condition affecting genetically susceptible individuals, characterized by inflammatory damage to the small intestine following ingestion of wheat gluten or barley and rye products. The only life-long treatment is strict gluten-free diet which is difficult personally and socially, affects quality of life, not widely available, more expensive, with lower palatability, resulting in low compliance. No doubt, there is therefore an urgent need for alternative therapeutic modalities. Based on the increasing knowledge on the sequential pathophysiological events driving the intestinal inflammatory cascade, new attractive and potential therapies were starting to immerge: selecting, changing, degrading, manipulating or binding the dietary toxic environmental factors, decreasing intestinal permeability toward gluten or blocking the deamination of gluten by inhibiting tissue transglutaminase or the HLA-DQ presenting groove by carefully designed false peptide, shifting the typical Th1 to Th2 inflammatory reaction or antagonizing major proinflammatory cytokines, enhancing regulatory immune function or developing preventive vaccines, blocking adhesion molecule, inducing gluten oral or intranasal tolerance or applying epithelial repairing mitogens to oppose the mucosal destruction. Safety, effectiveness, cost and affordability are prime issues to consider. Some modalities have shown promising results in vitro. Future will show who will win the race.

Pediatric Crohn's Disease and Growth Retardation: The Role of Genotype, Phenotype, and Disease Severity

Background. Delayed growth is a well-established feature of pediatric Crohns disease. Several factors have been shown to affect growth, including disease location, severity, and treatment. The recently discovered NOD2 gene has been correlated to ileal location of Crohns disease and subsequently could affect growth through the resulting phenotype or as an independent risk factor. The aim of our study was to determine if growth retardation is affected by genotype independently of disease location or severity. Methods. Genotyping for 3 NOD2 single-nucleotide polymorphisms was performed in 93 patients with detailed growth records. Parameters including disease location, disease severity, and NOD 2 genotype and their effect on z scores for height and weight at disease onset and during follow-up were analyzed. Results. NOD2 mutations were correlated with ileal location but not with disease severity or growth retardation. Ileal involvement was significantly associated with height retardation at disease onset and the lowest z score during follow-up. Use of steroids affected weight but not height. Regression models for growth variables revealed that the strongest association with impaired growth is with disease severity (weight- and height-failure odds ratios: 6.17 and 4.52, respectively). Conclusions. Severity of disease is correlated with growth failure for both height and weight. Location of disease is a weaker predictor of disordered growth and is correlated with growth retardation but not growth failure. The NOD2 genotype was not correlated with growth retardation or growth failure.

Molecular and clinical characteristics in 46 families affected with Peutz-Jeghers syndrome

Germline mutations of the tumor suppressor gene LKB1/STK11 are responsible for the Peutz–Jeghers syndrome (PJS), an autosomal-dominant disorder characterized by mucocutaneous pigmentation, hamartomatous polyps, and an increased risk of associated malignancies. In this study, we assessed the presence of pathogenic mutations in the LKB1/STK11 gene in 46 unrelated PJS families, and also carried genotype–phenotype correlation in regard of the development of cancer in 170 PJS patients belonging to these families. All LKB1/STK11 variants detected with single-strand conformational polymorphism were confirmed by direct sequencing, and those without LKB1/STK11 mutation were further submitted to Southern blot analysis for detection of deletions/rearrangements. Statistical analysis for genotype–phenotype correlation was performed. In 59% (27/46) of unrelated PJS cases, pathogenic mutations in the LKB1/STK11 gene, including 9 novel mutations, were identified. The new mutations were 2 splice site deletion–insertions, 2 missenses, 1 nonsense, and 4 abnormal splice sites. Genotype–phenotype analysis did not yield any significant differences between patients carrying mutations in LKB1/STK11 versus those without mutations, even with respect to primary biliary adenocarcinoma. This study presents the molecular characterization and cancer occurrence of a large cohort of PJS patients, increases the mutational spectrum of LKB1/STK11 allelic variants worldwide, and provides a new insight useful for clinical diagnosis and genetic counseling of PJS families.

Rheumatoid arthritis-celiac disease relationship: joints get that gut feeling.

Rheumatoid arthritis (RA) and celiac disease (CD) belong to the autoimmune disease family. Despite being separate entities they share multiple aspects. Epidemiologically they share comparable incidence environmental influences, associated antibodies and a recent incidental surge. They differ in their HLA pre-dispositions and specific predictive and diagnostic biomarkers. At the clinical level, celiac disease exhibits extra-intestinal rheumatic manifestations and RA gastrointestinal ones. Small bowel pathology exists in rheumatic patients. A trend towards responsiveness to a gluten free diet has been observed, ameliorating celiac rheumatic manifestations, whereas dietary interventions for rheumatoid arthritis remain controversial. Pathophysiologically, both diseases are mediated by endogenous enzymes in the target organs. The infectious, dysbiotic and increased intestinal permeability theories, as drivers of the autoimmune cascade, apply to both diseases. Contrary to their specific HLA pre-disposition, the diseases share multiple non-HLA loci. Those genes are crucial for activation and regulation of adaptive and innate immunity. Recently, light was shed on the interaction between host genetics and microbiota composition in relation to CD and RA susceptibility, connecting bugs and us and autoimmunity. A better understanding of the above mentioned similarities in the gut-joint inter-relationship, may elucidate additional facets in the mosaic of autoimmunity, relating CD to RA.

Increased Prevalence of Autoantibodies in Celiac Disease

Several features suggest an immune mechanismoperates in celiac disease. Information on theautoantibody repertoire in this condition is lacking.The purpose of the study was to investigate thereactivity of celiac patients sera to various autoantigenswidely distributed in the human intestine. Seventychildren, celiacs and controls, were evaluated for serumautoantibodies using ELISA and immunofluorescence. Celiac patients had increased prevalence ofserum anti-single-stranded DNA (14%),anti-double-stranded DNA (23%), anticardiolipin (14%),and anti-endomysial autoantibodies (63%). The relevanceof this finding on the extraintestinal manifestations of celiacdisease or the coexistence of autoimmune conditions andceliac disease remains to be determined.

Possible association between celiac disease and bacterial transglutaminase in food processing: a hypothesis

The incidence of celiac disease is increasing worldwide, and human tissue transglutaminase has long been considered the autoantigen of celiac disease. Concomitantly, the food industry has introduced ingredients such as microbial transglutaminase, which acts as a food glue, thereby revolutionizing food qualities. Several observations have led to the hypothesis that microbial transglutaminase is a new environmental enhancer of celiac disease. First, microbial transglutaminase deamidates/transamidates glutens such as the endogenous human tissue transglutaminase. It is capable of crosslinking proteins and other macromolecules, thereby changing their antigenicity and resulting in an increased antigenic load presented to the immune system. Second, it increases the stability of protein against proteinases, thus diminishing foreign protein elimination. Infections and the crosslinked nutritional constituent gluten and microbial transglutaminase increase the permeability of the intestine, where microbial transglutaminases are necessary for bacterial survival. The resulting intestinal leakage allows more immunogenic foreign molecules to induce celiac disease. The increased use of microbial transglutaminase in food processing may promote celiac pathogenesis ex vivo, where deamidation/transamidation starts, possibly explaining the surge in incidence of celiac disease. If future research substantiates this hypothesis, the findings will affect food product labeling, food additive policies of the food industry, and consumer health education.