Kinetics of mucosal granulocyte activation after gluten challenge in coeliac disease

Evaluation of biomarkers for ulcerative colitis comparing two sampling methods: fecal markers reflect colorectal inflammation both macroscopically and on a cellular level

OBJECTIVE

Simple, objective and inexpensive tools for the assessment of mucosal inflammation in ulcerative colitis (UC) are highly desirable. The aim of this study was to evaluate a broad spectrum of activity markers comparing two sampling methods: fecal samples and the mucosal patch technique.

METHODS

Twenty patients with active UC and 14 healthy controls were characterized by means of clinical indices and endoscopy together with histology and immunohistochemistry on colorectal sections. Neutrophil myeloperoxidase (MPO), calprotectin, eosinophil cationic protein (ECP), eosinophil protein X (EPX/EDN) and IL-1β were analyzed in fecal samples and rectal fluid collected by the patch technique. Nitric oxide (NO) was analyzed in rectal gas samples. Expression of activity markers on colorectal neutrophils and eosinophils were analyzed by flow cytometry.

RESULTS

All fecal and patch markers were increased in UC patients compared with healthy controls. Fecal markers and the level of neutrophil activation correlated to disease activity, whereas patch markers did not. The best markers in terms of discriminative power were fecal MPO and IL-1β. Fecal marker levels were related to sigmoidal histology scores and to neutrophil number and activation. Patch markers were related to rectal inflammation only.

CONCLUSIONS

The levels of inflammation markers in feces and patch fluid distinctly reflected active inflammation in UC. The degree of disease activity was however best assessed by fecal markers, particularly MPO and IL-1β. Fecal markers reflect colorectal inflammation both macroscopically and on a cellular level, and may be useful for the evaluation of subclinical inflammation. The applicability of patch markers is restricted to rectal inflammation.

Gliadin Induces Neutrophil Migration via Engagement of the Formyl Peptide Receptor, FPR1

Background

Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induce the production of Interleukin-8, a potent neutrophil-activating and chemoattractant chemokine. We sought to study the involvement of neutrophils in the early immunological changes following gliadin exposure.

Methods

Utilizing immunofluorescence microscopy and flow cytometry, the redistribution of major tight junction protein, Zonula occludens (ZO)-1, and neutrophil recruitment were assessed in duodenal tissues of gliadin-gavaged C57BL/6 wild-type and Lys-GFP reporter mice, respectively. Intravital microscopy with Lys-GFP mice allowed monitoring of neutrophil recruitment in response to luminal gliadin exposure in real time. In vitro chemotaxis assays were used to study murine and human neutrophil chemotaxis to gliadin, synthetic alpha-gliadin peptides and the neutrophil chemoattractant, fMet-Leu-Phe, in the presence or absence of a specific inhibitor of the fMet-Leu-Phe receptor-1 (FPR1), cyclosporine H. An irrelevant protein, zein, served as a control.

Results

Redistribution of ZO-1 and an influx of CD11b⁺Lys6G⁺ cells in the lamina propria of the small intestine were observed upon oral gavage of gliadin. In vivo intravital microscopy revealed a slowing down of GFP⁺ cells within the vessels and influx in the mucosal tissue within 2 hours after challenge. In vitro chemotaxis assays showed that gliadin strongly induced neutrophil migration, similar to fMet-Leu-Phe. We identified thirteen synthetic gliadin peptide motifs that induced cell migration. Blocking of FPR1 completely abrogated the fMet-Leu-Phe-, gliadin- and synthetic peptide-induced migration.

Conclusions

Gliadin possesses neutrophil chemoattractant properties similar to the classical neutrophil chemoattractant, fMet-Leu-Phe, and likewise uses FPR1 in the process.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Dermatitis herpetiformis: from the genetics to the development of skin lesions

Dermatitis herpetiformis (DH) is a rare autoimmune disease linked to gluten sensitivity with a chronic-relapsing course. It is currently considered to be the specific cutaneous manifestation of celiac disease (CD). Both conditions are mediated by the IgA class of autoantibodies, and the diagnosis of DH is dependent on the detection of granular deposits of IgA in the skin. There is an underlying genetic predisposition to the development of DH, but environmental factors are also important. This paper describes these different factors and discusses the known mechanism that lead to the development of skin lesions.

Identification of a novel immunomodulatory gliadin peptide that causes interleukin-8 release in a chemokine receptor CXCR3-dependent manner only in patients with coeliac disease

The autoimmune enteropathy, coeliac disease (CD), is triggered by ingestion of gluten-containing grains. We recently reported that the chemokine receptor CXCR3 serves as a receptor for specific gliadin peptides that cause zonulin release and subsequent increase in intestinal permeability. To explore the role of CXCR3 in the immune response to gliadin, peripheral blood mononuclear cells from both patients with CD and healthy controls were incubated with either pepsin-trypsin-digested gliadin or 11 α-gliadin synthetic peptides in the presence or absence of a blocking anti-CXCR3 monoclonal antibody. Supernatants were analysed for interleukin-6 (IL-6), IL-8, IL-10, IL-13, IP-10 (CXCL10), tumour necrosis factor-α and interferon-γ. Gliadin broadly induced cytokine production irrespective of the clinical condition. However, IL-8 production occurred only in a subgroup of individuals and cells of the phagocytic lineage were the main source. Induction of IL-8 was reproduced by one of a comprehensive panel of synthetic α-gliadin peptides and was abrogated when CXCR3 was blocked before stimulation with either gliadin or this peptide in the CD group but not in the control group, suggesting that gliadin-induced IL-8 production was CXCR3-dependent gliadin induced IL-8 production only in CD.

Fecal calprotectin concentration in celiac disease

GOALS

We aimed to determine fecal calprotectin (FC) concentration and its relation with histopathologic findings of children with celiac disease (CD) and to observe the probable alterations under gluten-free diet (GFD).

BACKGROUND

As FC is regarded as a marker of inflammation in the gastrointestinal tract, we hypothesized that it might be increased in untreated CD.

STUDY

The study included 29 newly diagnosed patients with CD (mean age: 6.6+/-0.6 y) and sex and age-matched 10 healthy children. All of the children with CD admitted to the hospital were classical form who has chronic diarrhea and failure to thrive. The degree of mucosal damage was graded according to the modified Marsh criteria. FC concentration was determined by enzyme-linked immunosorbent assay method on admission and after 1 year of GFD.

RESULTS

Mean FC concentration of children with CD on admission and of healthy children were 13.40+/-8.5 and 4.3+/-3.3 mg/L, respectively (P=0.004). FC concentration under GFD was 4.6+/-2.7 mg/L and there was a significant statistical difference between untreated patients and those under GFD for 1 year (P=0.001). There was no statistical difference between FC concentration of those under GFD and healthy children (P=0.8). Mean FC concentrations of children with total-villous atrophy and partial-villous atrophy were significantly different (13.8+/-9.3 mg/L vs. 3.7+/-1.8 mg/L, P=0.005).

CONCLUSIONS

It was found that FC concentration is increased in childhood CD, related to the severity of histopathologic findings and responsive to GFD. The pathogenetic mechanism by which FC is increased in CD should be investigated in further studies.

Self-reported food intolerance and mucosal reactivity after rectal food protein challenge in patients with rheumatoid arthritis

OBJECTIVES

A dietary link to rheumatoid arthritis (RA) has been suspected and an influence on arthritic symptoms by different diets has been reported. Our primary aim was to record the self-experienced adverse food reactions in patients with RA. A secondary aim was to relate self-experienced adverse reactions to dairy produce and wheat to the local mucosal reactivity observed after rectal challenge with cow's milk protein (CM) and wheat gluten.

METHODS

A questionnaire about self-experienced adverse reaction to food was sent to 347 RA patients. Rectal challenge with CM and gluten was performed in 27 of these patients and in healthy controls (n = 18). After a 15-h challenge the mucosal production of nitric oxide (NO) and the mucosal release of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were measured by using the mucosal patch technique.

RESULTS

Twenty-seven per cent of the RA patients reported food intolerance (FI) to various foods, and in particular to CM, meat, and wheat gluten. Strong mucosal reactivity to CM was observed in 11% of the patients. Moderately increased mucosal reactivity to CM and gluten was found in 22% and 33%, respectively, of the patients. No relationship was found between self-experienced adverse reactions to CM or gluten and mucosal reactivity to these proteins.

CONCLUSIONS

Perceived FI is reported frequently by RA patients, with a prevalence similar to that reported previously in the general population. Mucosal reactivity to CM and gluten is seen in a minor fraction of RA patients and is not related to the frequently perceived intolerance to these proteins.

Cow's milk protein sensitivity assessed by the mucosal patch technique is related to irritable bowel syndrome in patients with primary Sjögren's syndrome

Introduction

Patients with primary Sjögren's syndrome (pSS) are reported to have a variety of gastrointestinal symptoms partly attributed to an overrepresentation of celiac disease. We have observed that irritable bowel syndrome (IBS)-like symptoms are frequent complaints in this patient group. Allergic manifestations to various drugs are also common in pSS. A role of food allergy in IBS has been proposed.

Objective

This study is aimed at evaluating the mucosal response to rectal challenge with cow's milk protein (CM) in patients with pSS and relates possible CM reactivity to their intestinal symptoms.

Methods

A rectal challenge with CM was performed in 21 patients with pSS and 18 healthy controls. Fifteen hours after challenge the mucosal production of nitric oxide (NO) and the release of myeloperoxidase (MPO) as signs of mucosal inflammatory reaction were measured using the mucosal patch technique.

Results

Eight out of 21 patients with pSS had a definite increase of mucosal NO synthesis and the luminal release of MPO after rectal CM challenge. This sign of milk sensitivity was not linked to IgG/IgA antibodies to milk proteins. The symptoms for IBS according to Rome III criteria were fulfilled in 13 patients. All patients who were CM sensitive suffered from IBS. In a small open study, patients reactive to CM reported an improvement of intestinal symptoms on a CM-free diet.

Conclusion

A rectal mucosal inflammatory response after CM challenge is seen in 38% of patients with pSS as a sign of CM sensitivity. IBS-like symptoms were common in pSS, linked to CM sensitivity.

Serum IL-8 in Patients with Dermatitis Herpetiformis is Produced in Response to Dietary Gluten

Patients with dermatitis herpetiformis (DH) have a gluten-sensitive enteropathy and while on gluten-containing diets have elevated levels of serum IL-8. We hypothesized that the mucosal immune response to gluten is responsible for the elevated serum IL-8. Six DH patients were studied while on a gluten-free diet (GFD), whereas four continued on a normal diet. Patients were followed for a mean 2.2 years and serum IL-8 was analyzed. Small bowel biopsies from five DH patients on normal diets, two DH patients on GFD, and six subjects with no small bowel abnormalities were analyzed for IL-8 mRNA. Serum IL-8 levels normalized in five of six patients on GFD and decreased in one, whereas serum IL-8 levels showed no statistically significant change in DH patients on normal diets. Small bowel biopsies from DH patients on normal diets had increased expression of IL-8 mRNA compared to normal subjects, whereas patients on a GFD showed no significant increase in small bowel mRNA. No significant IL-8 mRNA was detected in normal skin biopsies from patients with DH. These observations suggest that the IL-8 in the serum of patients with DH originates from the small bowel as a mucosal immune response to gluten ingestion.

Faecal calprotectin concentrations in untreated coeliac patients

OBJECTIVE

Calprotectin is a granulocyte cytosolic protein that is considered to be a promising marker of subclinical inflammation. High faecal calprotectin concentrations (FCCs) have been found in several intestinal diseases, but no data are currently available on patients with coeliac disease. The purpose of this pilot study was to evaluate FCCs in untreated coeliac patients and to correlate them with clinical score and histological characteristics.

MATERIAL AND METHODS

Twenty-eight consecutive coeliac patients were recruited. Thirty healthy adult volunteers participated as the control group. FCCs were determined by ELISA. Clinical assessment was carried out in all patients. The histological severity of lesions and the infiltration of neutrophil polymorphs in the intestinal mucosa were also evaluated. Mean FCCs in patients and the control group were compared by means of the t-test for independent samples. In coeliac patients, differences in FCCs in subgroups identified by clinical score, lesion severity and neutrophil infiltration were evaluated by the Kruskal-Wallis non-parametric test.

RESULTS

FCCs in untreated coeliac patients were not significantly different from those in controls (p=0.163). Among coeliac patients, FCCs were not significantly different in relation to the level of clinical score, lesion severity or neutrophil infiltration (p=0.92, p=0.96 and p=0.74, respectively).

CONCLUSIONS

This study shows, for the first time, that FCCs in untreated coeliac patients do not differ significantly from those in controls.

Gluten sensitivity in patients with primary Sjögren's syndrome

OBJECTIVE

To evaluate the rectal mucosal response to gluten as an indication of gluten sensitivity in patients with primary Sjögren's syndrome (pSS).

MATERIAL AND METHODS

Rectal challenges with wheat gluten were performed in 20 patients with pSS and 18 healthy control subjects. Fifteen hours after challenge the mucosal production of nitric oxide (NO) was measured.

RESULTS

Five patients with pSS had a significant increase in the luminal release of NO after the rectal gluten challenge, indicating gluten sensitivity. All were HLA-DQ2 and/or -DQ8-positive. Two of the patients with increased NO had antibodies against transglutaminase and a duodenal biopsy showed an absolutely flat mucosa consistent with coeliac disease in one of the patients. Before gluten challenge, 15 of the Sjögren's syndrome (SS) patients reported gastrointestinal symptoms, and 8 reported intolerance to various food products. No correlation was found between gluten sensitivity and self-reported food intolerance or gastrointestinal symptoms.

CONCLUSIONS

Rectal mucosal inflammatory response after gluten challenge is often seen in patients with pSS, signifying gluten sensitivity. However, this reactivity is not necessarily linked to coeliac disease.

Mucosal reactivity to cow's milk protein in coeliac disease

Patients with coeliac disease (CD) on a gluten-free diet may still have gastrointestinal symptoms. On clinical grounds cow's milk (CM) protein sensitivity may be suspected. Here, using rectal protein challenge, we investigated the local inflammatory reaction to gluten and CM protein in adult patients with CD in remission. Rectal challenges with wheat gluten and dried CM powder were performed in 20 patients with CD and 15 healthy controls. Fifteen hours after challenge the mucosal reaction was recorded by the mucosal patch technique with measurements of local release of neutrophil and eosinophil granule constituents; myeloperoxidase (MPO) and eosinophil cationic protein (ECP). We measured the mucosal production of nitric oxide (NO) simultaneously. Six of the patients who reacted to CM were also challenged with alpha-lactalbumin and casein. In 18 of 20 patients gluten challenge induced neutrophil activation defined as increased MPO release and increased NO synthesis. Ten of these 20 patients showed a similarly strong inflammatory reaction to CM challenge. Six of the CM sensitive patients were challenged with specific CM proteins: casein and alpha-lactalbumin. Casein, in contrast to alpha-lactalbumin, induced an inflammatory response similar to that produced by CM. A mucosal inflammatory response similar to that elicited by gluten was produced by CM protein in about 50% of the patients with coeliac disease. Casein, in particular, seems to be involved in this reaction.

Coeliac disease: an update for pathologists

Coeliac disease is the manifestation of an immune hypersensitivity reaction towards gluten and related proteins, in genetically predisposed people. Although the precise pathogenesis of this condition remains to be fully elucidated, it is probably multifactorial in origin. The diagnosis of coeliac disease has traditionally depended on intestinal biopsies alone; nowadays, the diagnosis has been expanded to include an array of serological markers. This review is intended to offer pathologists an update of the relevant history and immunopathology pertaining to coeliac disease and also to offer recommendations on the ongoing responsibilities of the pathologist in the diagnosis and reporting of coeliac disease.

Advances in celiac disease

PURPOSE OF REVIEW

This article primarily aims to review critically research in all aspects of celiac disease over the last year. As always, there has been a wealth of relevant papers.

RECENT FINDINGS

The role of genetics in disease susceptibility is slowly becoming more clearly defined and a more detailed understanding of the disease processes at the molecular level is paving the way towards the development of specific targeted therapies.

SUMMARY

Despite recent advances in our understanding of celiac disease, the gluten-free diet remains the only current viable therapy and even with advances in serological tests and markers, the duodenal biopsy remains the gold standard for diagnosis and monitoring of the response to therapy.