Oral mucosa of coeliac disease patients produces antiendomysial and antitransglutaminase antibodies: the diagnostic usefulness of an in vitro culture system

Celiac Disease Causes Epithelial Disruption and Regulatory T Cell Recruitment in the Oral Mucosa

Celiac disease (CD) is a chronic autoimmune disease characterized by an immune-triggered enteropathy upon gluten intake. The only current treatment available is lifelong Gluten Free Diet (GFD). Several extraintestinal manifestations have been described in CD, some affecting the oral mucosa. Thus, we hypothesized that oral mucosa could potentially be a target for novel biomarkers and an administration route for CD treatment. Six de novo diagnosed and seven CD patients under GFD for at least 1 year were recruited. Non-celiac subjects (n = 8) were recruited as control group. Two biopsies of the cheek lining were taken from each subject for mRNA analysis and immunohistochemical characterization. We observed a significant decrease in the expression of epithelial junction proteins in all CD patients, indicating that oral mucosa barrier integrity is compromised. FoxP3+ population was greatly increased in CD patients, suggesting that Tregs are recruited to the damaged mucosa, even after avoidance of gluten. Amphiregulin mRNA levels from Peripheral Blood Mononuclear Cells (PBMCs) and epithelial damage in the oral mucosa correlated with Treg infiltration in all the experimental groups, suggesting that recruited Tregs might display a “repair” phenotype. Based on these results, we propose that oral mucosa is altered in CD and, as such, might have diagnostic potential. Furthermore, due to its tolerogenic nature, it could be an important target for oral immunotherapy.

Wheat-related disorders reviewed: making a grain of sense

Wheat-related disorders have become a growing area of clinical and scientific interest and can be categorized broadly as: autoimmune-mediated; allergic; and non-autoimmune/non-allergic conditions. Non-celiac gluten sensitivity (NCGS) and non-celiac wheat sensitivity (NCWS) present on this spectrum as disorders associated with adverse gastrointestinal and extra-intestinal manifestations following exposure to gluten and/or other wheat-related constituents. NCGS/NCWS is increasingly considered in patients with unexplained symptoms after the exclusions of celiac disease and wheat allergy. As objective diagnostic data and specific biomarkers are lacking, response to a gluten-free/wheat-free diet can confirm the presence of NCGS/NCWS. An association with irritable bowel syndrome has been detected, and the effects of other food components, such as fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, may contribute. Our organization and synthesis of extant knowledge pertaining to wheat-related disorders may advance current practice and research efforts toward an improved understanding of NCGS/NCWS as an evolving clinical entity.

Salivary proline-rich proteins and gluten: Do structural similarities suggest a role in celiac disease?

PURPOSE

Gluten proteins, the culprits in celiac disease (CD), show striking similarities in primary structure with human salivary proline-rich proteins (PRPs). Both are enriched in proline and glutamine residues that often occur consecutively in their sequences. We investigated potential differences in the spectrum of salivary PRPs in health and CD.

EXPERIMENTAL DESIGN

Stimulated salivary secretions were collected from CD patients, patients with refractory CD, patients with gastrointestinal complaints but no CD, and healthy controls. PRP isoforms/peptides were characterized by anionic and SDS-PAGE, PCR, and LC-ESI-MS.

RESULTS

The gene frequencies of the acidic PRP isoforms PIF, Db, Pa, PRP1, and PRP2 did not differ between groups. At the protein level, PRPs peptides showed minor group differences, but these could not differentiate the CD and/or refractory CDs groups from the controls.

CONCLUSIONS AND CLINICAL RELEVANCE

This extensive study established that salivary PRPs, despite similarity to gluten proteins, show no apparent correlation with CD and thus will not serve as diagnostic markers for the disease. The structural basis for the tolerance to the gluten-like PRP proteins in CD is worthy of further exploration and may lead to the development of gluten-like analogs lacking immunogenicity that could be used therapeutically.

Overview of biomarkers for diagnosis and monitoring of celiac disease

Among the adverse reactions caused by wheat, celiac disease (CD) is the longest studied and best-known pathology. The more recently defined non-celiac gluten sensitivity (NCGS) presents with symptoms which are often indistinguishable from CD. Diagnosis of CD is based on serologic, molecular, and bioptic testing. The IgA anti-transglutaminase (tTG) test is considered highly important, as it shows high sensitivity and specificity and its levels correlate to the degree of intestinal damage. Small bowel biopsy can be avoided in symptomatic patients with IgA anti-tTG levels above 10× the manufacturer's cut-off. Recently, tests of anti-deamidated peptides of gliadin (DGP) have replaced classic anti-native gliadin (AGA) tests. DGP assays have a considerably higher diagnostic accuracy than AGA assays, especially in the IgG class, and can replace anti-tTG tests in patients with selective IgA deficiency. The combination of IgG anti-DGP plus IgA anti-tTG assays show greater sensitivity than a single test, with very high specificity. EMA tests have great diagnostic accuracy but are not recommended by all the latest guidelines because they are observer dependent. Biopsy must still be considered the gold standard for CD diagnosis. HLA-DQ genotyping can be used to screen asymptomatic children and in cases of histology/serology disagreement. About half of NCGS patients are DQ2 positive and have IgG AGA. To diagnose NCGS, first CD and wheat allergy must be excluded; then the wheat dependence of symptoms must be verified by a gluten-free diet and subsequent gluten challenge.

Oral mucosa patch test: a new tool to recognize and study the adverse effects of dietary nickel exposure

On contact with the skin, nickel may cause allergic contact dermatitis, which can be diagnosed by an epicutaneous patch test. Nickel exposure via the intestinal mucosa can induce diarrhea, abdominal pain, and swelling. The aim of the present study was to investigate the relationship between these symptoms and nickel intake by means of a novel oral mucosa patch test. Eighty-six patients with intestinal symptoms related to ingestion of nickel-containing foods were submitted to epicutaneous and oral mucosa patch tests for nickel. All patients with positive oral mucosa patch test results were subject to a low-nickel diet and monitored over time. Skin lesions were observed in 33 out of 86 (38.4%) patients evaluated by the epicutaneous patch test. Mucosal lesions were seen in 53 out of 86 (61.6%) patients given the oral mucosa patch test. After 2 months of a low-nickel diet, 52 out of 53 (98.1%) patients showed an improvement of their symptoms. There is a significant correlation between response time of the oral mucosa patch test and the latency of symptoms after ingestion of nickel-containing foods. Consequently, the oral mucosa patch test can be used to recognize and study the adverse effects of dietary nickel exposure that could be defined as allergic contact mucositis. A low-nickel diet is also shown to be an effective treatment for this condition.

Orally based diagnosis of celiac disease: current perspectives

Celiac disease (CD) is a lifelong immune-mediated disorder caused by the ingestion of wheat gluten in genetically susceptible persons. Most cases of CD are atypical and remain undiagnosed, which exposes the individuals to the risk of life-threatening complications. Serologic endomysial and tissue transglutaminase antibody tests are used to screen at-risk individuals, although a firm diagnosis requires demonstration of characteristic histopathologic findings in the small-intestinal mucosa. A gluten challenge, with a repeat biopsy to demonstrate recurrence of histopathologic changes in the intestinal mucosa after the re-introduction of gluten, is considered for those persons in whom diagnosis remains in doubt. In this paper, we review studies that evaluated: (1) the possibility of using oral mucosa for the initial diagnosis of CD or for local gluten challenge; and (2) the possibility of using salivary CD-associated antibodies as screening tests. Our review shows that orally based diagnosis of CD is attractive and promising, although additional evaluations with standardized collection and analysis methods are needed. There is some evidence of a dissociation between systemic and oral mucosal immune responses in CD. The hypothesis that gluten could stimulate naive lymphocytes directly in the oral cavity would have important implications for the understanding, diagnosis, and management of CD.