Microscopic enteritis: novel prospect in coeliac disease clinical and immuno-histogenesis. Evolution in diagnostic and treatment strategies

Minimal Lesions of the Small Intestinal Mucosa: More than Morphology

Minimal lesions of the small bowel are mucosal changes characterized by an increased number of intraepithelial lymphocytes (with or without crypt hyperplasia) and normal villous architecture. Such changes are associated with a wide spectrum of conditions, ranging from food intolerances to infections, and from drugs to immune diseases, with different clinical profiles and manifestations, which complicates the formulation of a differential diagnosis. Patient history, symptom evaluation, and histopathology are the diagnostic features needed to establish a correct diagnosis. Physicians should assist pathologists in formulating a precise morphological evaluation by taking well-oriented small intestinal biopsies and collecting informative clinical findings that inform histopathology. In this current clinical controversy, the authors provide the reader with an appraisal of the small intestine minimal lesions through a careful analysis of the major conditions (e.g., celiac disease and other non-celiac disorders) responsible for such changes and their differential diagnosis. Also, we acknowledge that some of the diseases detailed in this article may progress from an early minimal lesion to overt mucosal atrophy. Thus, the timing of the diagnosis is of paramount importance.

Basal and Infectious Enteritis in Broilers Under the I See Inside Methodology: A Chronological Evaluation

Recently, the inflammation of the intestinal mucosa has been related to many diseases in humans and animals. The concept of Microscopic Enteritis (ME) used in human pathology through the Marsh classification system has no counter-part in veterinary medicine. In poultry science, the I See Inside (ISI) methodology, unlike the current linear measures of villi and crypts, generates possibilities to describe and understand the avian ME. Through specific parameters, graded from 0 to 3, the model links proliferative and/or inflammatory reactions in the intestinal layers to some loss in performance. Herein, two trials were conducted in order to describe the development of ME through the ISI methodology in chickens challenged or not with Eimeria spp. and Clostridium perfringens. In each trial, a total of 64 birds were divided in 2 treatments with 4 replicates containing 8 birds each: non-challenged (NCH) and challenged (CH) through gavage with an Eimeria spp. vaccine at 1 day of age and 10⁸ CFU/mL of Clostridium perfringens administered at 10, 11, and 12 days of age. At 7, 14, 21, and 28 days of age birds were euthanized and samples of ileum and liver were collected for ISI evaluation, cytokines and presence of macrophages, CD4+ and CD8+ cell. The results allowed the description of the avian Microscopic Enteritis and of its two basic components: a basal enteritis (BE) in NCH broilers, over which the infectious enteritis is developed in CH birds. In addition, the chronology of ME translated by the ISI methodology parameters were associated to losses in zootechnical performance.

Coeliac disease under a microscope: Histological diagnostic features and confounding factors

Coeliac disease (CD) and gluten-related disorders represent an important cornerstone of the daily practice of gastroenterologists, endoscopists and dedicated histopathologists. Despite the knowledge of clinical, serological and histological typical lesions, there are some conditions to consider for differential diagnosis. From the first description of histology of CD, several studies were conducted to define similar findings suggestive for microscopic enteritis. Considering the establishment of early precursor lesions, the imbalance of gut microbiota is another point still requiring a detailed definition. This review assesses the importance of a right overview in case of suspected gluten-related disorders and the several conditions mimicking a similar histology.

Lymphocytic duodenitis or microscopic enteritis and gluten-related conditions: what needs to be explored?

Microscopic enteritis (ME) is characterized by abnormal infiltration of intraepithelial lymphocytes in intestinal mucosa. It was described as duodenal lymphocytosis or lymphocytic duodenitis until the dedicated Consensus Conference of 2015. ME represents a common feature of several gluten-mediated and non-gluten related diseases; therefore, it is an umbrella term embracing several conditions. The most frequent causes of ME are gluten-related disorders (celiac disease, non-celiac gluten sensitivity, wheat allergy), Helicobacter pylori infection and drug-related damages. Less frequently, ME may be secondary to inflammatory bowel disease, some autoimmune conditions, immunoglobulin deficiencies, blood malignancies, infections and irritable bowel syndrome. Therefore, the differential diagnosis of ME may be challenging. The diagnosis of ME needs to be driven by predominant symptoms and patient history. However, it is often difficult to achieve an immediate identification of the underlying condition, and a broad variety of diagnostic tests may be required. Ultimately, long-term surveillance is needed for a final diagnosis in many cases, since a hidden or quiescent condition may be disclosed after a period of latency. In any case, strict collaboration between the clinician and the pathologist is pivotal. The treatment of ME should be personalized, depending on the underlying disease. For gluten-related conditions (celiac disease, gluten sensitivity, wheat allergy, dermatitis herpetiformis), a gluten-free diet may be proposed. For other conditions, a targeted etiologic treatment is necessary. In conclusion, ME represents a novel entity that is attracting increasing interest. The growing epidemiologic trend confirms that it will become a common condition in clinical practice.

Microscopic colitis in patients with mild duodenal damage: A new clinical and pathological entity (“lymphocytic enterocolitis”)?

AIM

To evaluate the potential association between mild duodenal damage and microscopic colitis (MC).

METHODS

We retrospectively included 105 consecutive patients with type I Marsh-Oberhuber duodenal damage and negativity for immunoglobulin A anti-endomysium and anti-tissue transglutaminase. The following parameters were analyzed: Sex, age at execution of esophagogastroduodenoscopy, duodenal damage, and number of intraepithelial lymphocytes at biopsies, prevalence of Helicobacter pylori infection, age at execution of colonoscopy, macroscopic and microscopic features of colonoscopy, family history of gastrointestinal and autoimmune diseases, smoking habits, biochemical parameters of inflammation and autoimmunity, use of proton pump inhibitors or nonsteroidal anti-inflammatory drugs, adverse reactions to drugs or foods, pathologies known to be associated with celiac disease or MC, living on a gluten-free diet or on a gluten-low diet for at least 1 mo.

RESULTS

Colonoscopy was performed in 59 patients, but only in 48 of them biopsies were taken in the entire colon. Considering the latter cohort, the diagnosis of MC was met in 25 (52.1%) patients while in 18 patients other pathologic findings were reported: 13 (27%) cases of nonspecific inflammatory bowel disease, 2 (4.2%) cases of Crohn’s disease, 2 (4.2%) cases of eosinophilic gastroenteritis, and 1 (2.1%) case of autoimmune enteritis. Five (10.4%) patients had a normal colonoscopic result. Matching the groups by age, and considering only patients who underwent colonoscopy (42.7 ± 15.5 years) vs those who did not undergo colonoscopy (36.9 ± 10.6 years), a statistical difference was found (P = 0.039). Focusing on symptoms, diarrhea was statistically more prevalent in MC group than in patients who did not undergo colonoscopy (P = 0.03).

CONCLUSION

Mild duodenal damage is associated with MC in more than half of the cases. This association supports the hypothesis of a link between these two entities.

May the assessment of baseline mucosal molecular pattern predict the development of gluten related disorders among microscopic enteritis?

AIM

To evaluate mucosal baseline mRNA expression of tissue transglutaminase 2 (tTG2), interferon gamma (IFNγ), toll-like receptor 2 (TLR2) and Myeloid Differentiation factor 88 (MyD88) in patients with microscopic enteritis (ME).

METHODS

We retrospectively enrolled 89 patients with ME of different etiology, which was defined within a 2-year mean period of follow-up. Baseline histological examination was performed on Hematoxylin-Eosin stained sections and CD3 lymphocyte immunohistochemistry was used for intraepithelial lymphocyte count (IELs). ME was defined according to the criteria of Bucharest Consensus Conference. For each patient, formalin embedded biopsy samples of the duodenum referred to the period of ME diagnosis were retrieved. Real-time polymerase chain reaction (RT-PCR) was used to detect the amount of mRNA coding for tTG2, IFNγ, TLR2 and MyD88, and the quantity was expressed as fold change compared to controls. Control group was represented by duodenal normal specimens from 15 healthy subjects undergoing endoscopy for functional symptoms. Comparisons among continuous variables were performed by One way analysis of variance (ANOVA) and Bonferroni’s test. The χ² test was used for categorical variables. Pearson’s test was used to evaluate correlations. Receiver operating curves were drawn for all four markers to estimate sensitivity and specificity in discriminating the development of CD and GS.

RESULTS

After a period of follow up of 21.7 ± 11.7 mo, the following diagnoses were achieved: gluten related disorders in 48 subjects (31 CD; 17 GS) and non-gluten related ones in 41 (29 Irritable Bowel Syndrome - IBS; 12 Others). CD patients had the highest tTG2 levels (8.3 ± 4.5). The ANOVA plus Bonferroni analysis showed that CD > Other ME > GS = IBS > negative controls. A cut off value of 2.258 was able to discriminate between CD and GS with a sensitivity of 52.94% and a specificity of 87.1%. Additionally, CD patients had the highest IFNγ levels (8.5 ± 4.1). ANOVA plus Bonferroni demonstrated CD > Other ME > GS = IBS > negative controls. A cut off of 1.853 was able to differentiate CD and GS with a sensitivity of 47.06% and a specificity of 96.77%. Patients with non gluten-related causes of ME exhibited the highest TLR2 levels (6.1 ± 1.9) as follows: Other ME > CD = GS = IBS > negative controls. TLR2 was unable to discriminate CD from GS. Patients with CD overexpressed MyD88 levels similarly to non gluten-related causes of DL (7.8 ± 4.9 and 6.7 ± 2.9), thus CD = Other ME > GS = IBS > negative controls. A cut off of 3.722 was able to differentiate CD from GS with a sensitivity of 52.94% and a specificity of 74.19%. IELs count (15-25 and more than 25/100 enterocytes) strongly correlated with mRNA levels of all tested molecules (P < 0.0001).

CONCLUSION

Our results confirm that a single marker is unable to predict a discrimination among ME underlying conditions as well as between CD and GS. Mucosal high levels of tTG and IFNγ mRNA may predict the development of CD more than GS with high specificity, despite an expected low sensitivity. TLR2 does not discriminate the development of CD from GS. MyD88 levels indicate that intestinal permeability is more increased when a severe intestinal damage underlies ME in both gluten related and unrelated conditions. Therefore, the results of the present paper do not seem to show a clear translational value.

Plasticity of the brush border - the yin and yang of intestinal homeostasis

The brush border on the apical surface of enterocytes is a highly specialized structure well-adapted for efficient digestion and nutrient transport, whilst at the same time providing a protective barrier for the intestinal mucosa. The brush border is constituted of a densely ordered array of microvilli, protrusions of the plasma membrane, which are supported by actin-based microfilaments and interacting proteins and anchored in an apical network of actomyosin and intermediate filaments, the so-called terminal web. The highly dynamic, specialized apical domain is both an essential partner for the gut microbiota and an efficient signalling platform that enables adaptation to physiological stimuli from the external and internal milieu. Nevertheless, genetic alterations or various pathological stresses, such as infection, inflammation, and mechanical or nutritional alterations, can jeopardize this equilibrium and compromise intestinal functions. Long-time neglected, the intestinal brush-border shall be enlightening again as the central actor of the complex but essential intestinal homeostasis. Here, we review the processes and components involved in brush border organization and discuss pathological mechanisms that can induce brush border defects and their physiological consequences.

Microscopic enteritis: Bucharest consensus

Microscopic enteritis (ME) is an inflammatory condition of the small bowel that leads to gastrointestinal symptoms, nutrient and micronutrient deficiency. It is characterised by microscopic or sub-microscopic abnormalities such as microvillus changes and enterocytic alterations in the absence of definite macroscopic changes using standard modern endoscopy. This work recognises a need to characterize disorders with microscopic and submicroscopic features, currently regarded as functional or non-specific entities, to obtain further understanding of their clinical relevance. The consensus working party reviewed statements about the aetiology, diagnosis and symptoms associated with ME and proposes an algorithm for its investigation and treatment. Following the 5^th International Course in Digestive Pathology in Bucharest in November 2012, an international group of 21 interested pathologists and gastroenterologists formed a working party with a view to formulating a consensus statement on ME. A five-step agreement scale (from strong agreement to strong disagreement) was used to score 21 statements, independently. There was strong agreement on all statements about ME histology (95%-100%). Statements concerning diagnosis achieved 85% to 100% agreement. A statement on the management of ME elicited agreement from the lowest rate (60%) up to 100%. The remaining two categories showed general agreement between experts on clinical presentation (75%-95%) and pathogenesis (80%-90%) of ME. There was strong agreement on the histological definition of ME. Weaker agreement on management indicates a need for further investigations, better definitions and clinical trials to produce quality guidelines for management. This ME consensus is a step toward greater recognition of a significant entity affecting symptomatic patients previously labelled as non-specific or functional enteropathy.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Allele and haplotype frequencies for HLA-DQ in Iranian celiac disease patients

AIM: To assess the distribution of human leukocyte antigen (HLA)-DQ2 and -DQ8 in Iranian celiac disease (CD) patients and compare them to healthy Iranian controls.

METHODS: To predict the HLA-DQA1 and -DQB1 genes, we used six previously reported HLA-tagging single nucleotide polymorphism to determine HLA genotypes in 59 Iranian patients with ‘biopsy-confirmed’ CD and in 151 healthy Iranian individuals. To test the transferability of the method, 50 cases and controls were also typed using a commercial kit that identifies individual carriers of DQ2, DQ7 and DQ8 alleles.

RESULTS: In this pilot study 97% of CD cases (n = 57) and 58% of controls (n = 87) were carriers of HLA-DQ2 and/or HLA-DQ8 heterodimers, either in the homozygous or heterozygous state. The HLA-DQ pattern of these 57 CD patients: heterozygous DQ2.2 (n = 14) and homozygous DQ2.2 (n = 1), heterozygous DQ2.5 (n = 33) and homozygous DQ2.5 (n = 8), heterozygous DQ8 (n = 13) and homozygous DQ8 (n = 2). Two CD patients were negative for both DQ2 and DQ8 (3%).

CONCLUSION: The prevalence of DQ8 in our CD population was higher than that reported in other populations (25.4%). As reported in other populations, our results underline the primary importance of HLA-DQ alleles in the Iranian population’s susceptibility to CD.

The irritable bowel syndrome-celiac disease connection

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder that has a significant impact on quality of life and health care resources. Celiac disease (CD), a gluten-sensitive enteropathy, can be mistaken for IBS. This article discusses the connection between IBS and CD and the new concept of nonceliac gluten sensitivity (NCGS). NCGS may occur in the presence of a normal or near-normal small bowel biopsy. Some patients with IBS without CD may derive symptomatic benefit from a gluten-free diet. Future research could facilitate a significant impact on the quality of life in this potential subgroup of patients.

Emerging concepts: from coeliac disease to non-coeliac gluten sensitivity

The rise in gluten consumption over time has led to the increasing recognition of coeliac disease (CD) with associated complications. However, only recently has there been an appreciation that the spectrum of gluten-related disorders is greater than just CD, which may explain the growing global popularity in gluten-free products. Current literature suggests that a newly recognised clinical entity in the form of non-coeliac gluten sensitivity (NCGS) may be the most common gluten-related disorder encountered by healthcare professionals, although its exact prevalence is as yet unknown. This article will review the historical relationship between mankind and gluten as well as the progressive recognition that it is possible for gluten to have a deleterious effect on our health. To this effect we discuss the prevalence, diagnosis and complications of CD including the benefits derived from a gluten-free diet (GFD). Finally, we discuss our current understanding of NCGS, in addition to highlighting the need for further research to determine the extent, clinicopathological features and serological biomarkers to help recognise this emerging condition in clinical practice.

[Gluten-sensitive enteropathy and functional dyspepsia]

Gluten-sensitive enteropathy (GSE) is increasingly diagnosed in adults. The symptoms of this disease can overlap with those of functional dyspepsia. The prevalence of GSE in dyspepsia has been reported to be 1.2-6.2% and could be higher if the entire spectrum of lesions related to gluten sensitivity, including lymphocytic enteropathy, is considered. Patients with dyspepsia secondary to GSE could be mistakenly diagnosed with functional dyspepsia unless upper gastrointestinal endoscopy is completed with duodenal biopsy and immunostaining for intraepithelial lymphocytes. A missed diagnosis could have major consequences in terms of morbidity and mortality and quality of life. Consequently, endoscopic study of patients with dyspepsia should be completed by duodenal biopsy when there are symptoms suggestive of GSE.

A prospective study of duodenal bulb biopsy in newly diagnosed and established adult celiac disease

OBJECTIVES

Recent reports suggest that the duodenal bulb may be the only site to demonstrate villous atrophy (VA) in celiac disease. However, there is a paucity of data from newly diagnosed adult celiac patients and no data from those patients with established celiac disease. The objective of this study was to compare the histological findings in the duodenal bulb and distal duodenum of patients with adult celiac disease (newly diagnosed or established) against controls.

METHODS

A total of 461 patients were prospectively recruited. Biopsies were graded using the Marsh criteria.

RESULTS

In all, 461 patients (300 females and 161 males) with median age 51 years were analyzed. In all, 126 had newly diagnosed celiac disease, 85 established celiac disease, and 250 controls. New diagnosis celiac disease (9%, P<0.0001) and established celiac disease (14%, P<0.0001) were more likely than controls to have VA in the bulb alone. Overall, when comparing the histological lesion of the bulb against the distal duodenum, 31/85 with established celiac disease (P<0.0001) and 21/126 newly diagnosed (P=0.0067) had a discrepancy in the severity of the lesion between the two sites compared with 18/250 controls. In all, 24/31 with established celiac disease and 16/21 newly diagnosed had the more severe lesion in the bulb.

CONCLUSIONS

VA may be present only in the duodenal bulb. This study suggests that the optimal assessment of patients in whom celiac disease is suspected (with positive serology) and those with established celiac disease requires a duodenal bulb biopsy in addition to distal duodenal biopsies.

Clinical and histological presentation of Helicobacter pylori and gluten related gastroenteropathy

BACKGROUND

Celiac disease has been reported to be associated with gastric abnormalities. The aim of this study was to assess the relationship between the prevalence of celiac disease and Helicobacter pylori infection in an Iranian population of 250 patients.

METHODS

Biopsies were taken from the gastric antrum and duodenum. Morphology and histology were evaluated using the updated Sydney system and modified Marsh criteria, respectively. To simplify the interpretation of gastric lesions we classified gastritis in macroscopic and microscopic stages. Serology for anti-tissue transglutaminase antibody was performed to determine the presence of celiac disease.

RESULTS

Among 250 patients, 232 (93%) had histological evidence of Helicobacter pylori infection. Histological abnormalities (Marsh I to IIIc) were present in 24 (10%). Of 24 patients, 20 (83%) with histological abnormalities were infected with Helicobacter pylori. Of 250 patients, 25 (10%) had a positive anti-tissue transglutaminase antibody. Of 25 anti-tissue transglutaminase antibody positive patients, 9 (3.6%) had microscopic and macroscopic enteritis (Marsh I to IIIc).

CONCLUSIONS

Clinical presentation of celiac disease was not distinguishable from cases infected with Helicobacter pylori. Histology, even in patients with positive serology, was non-specific and unhelpful. We found a high prevalence of Helicobacter pylori infection and chronic gastritis, but neither was associated with celiac disease, in agreement with studies in Western populations.

Coeliac disease in autoimmune liver disease: a cross-sectional study and a systematic review

BACKGROUND

Several studies have reported an association between coeliac disease and autoimmune liver disease, but there is little information on the prevalence of coeliac disease in certain autoimmune liver diseases, particularly from non-European, non-American countries.

AIMS

To investigate prevalence of coeliac disease in autoimmune liver disease in Iran and to summarize previous literature.

METHODS

We investigated prevalence of coeliac disease among 100 autoimmune liver disease patients and compared it with the prevalence in healthy individuals. We also performed an extensive search of the English literature in PubMed Database.

RESULTS

We found substantially elevated prevalence of coeliac disease in patients with overlap syndrome (10-15%) compared to the general population (0.1-1%). To a lesser extent, the prevalence was high in patients with autoimmune hepatitis (2-4%). In our systematic review, prevalence of coeliac disease in autoimmune hepatitis in the majority of studies was 4% or more; several studies also reported such prevalence in primary biliary cirrhosis.

CONCLUSIONS

Since coeliac disease is common among patients with autoimmune liver disease, screening autoimmune liver disease patients for coeliac disease is indicated. Although the magnitude of benefit from a gluten-free diet in reversing autoimmune liver disease in patients with coeliac disease is controversial, it may reduce the risk of further complications of coeliac disease.

Microscopic enteritis and pathomechanism of malabsorption

Microscopic enteritis (ME) is the stage of microscopic and sub-microscopic changes (microenteropathy) associated with the symptoms of gluten sensitive enteropathy leading to micronutrient deficiencies. It is characterized by subtle mucosal abnormalities without prominent inflammation, villous effacement, erosions or ulcerations on conventional light microscopy. The intraepithelial lymphocytes are usually in normal range <25/100 enterocytes (microenteropathy) or increased (lymphocytic enteritis). ME is the entity behind atypical forms of CD previously known as potential and latent CD. Systemic inflammation predominantly is found to be engaged in pathophysiology of micro-nutrient deficiency even in absence of macroscopic mucosal changes.

Symptoms and signs in individuals with serology positive for celiac disease but normal mucosa

Background

Antibody serology is an important tool in the investigation of celiac disease (CD), but does not always correlate with mucosal appearance in the small intestine. Patients with positive CD serology but normal mucosa (Marsh 0) are at increased risk of future CD. In this study we describe a model for identifying and characterizing individuals with normal mucosa but positive CD serology. Such individuals are sometimes referred to as having latent CD.

Methods

The records of ten Swedish pathology departments were used to identify individuals with biopsies indicating normal duodenal/jejunal mucosa. Using the national personal identification number, these data were linked with CD serology data (antigliadin, antiendomysial and tissue transglutaminase antibodies); and we thereby identified 3,736 individuals with normal mucosa but positive CD serology. Two independent reviewers then manually reviewed their biopsy reports to estimate comorbidity. We also randomly selected 112 individuals for validation through patient chart review.

Results

The majority of the 3,736 individuals were females (62%). Children (0–15 years) made up 21.4%. The median number of biopsy specimen was 3. Our review of biopsy reports found that other gastrointestinal comorbidity was rare (inflammatory bowel disease: 0.4%; helicobacter pylori infection: 0.2%). Some 22% individuals selected for patient chart review had a relative with CD. The most common symptoms among these individuals were diarrhea (46%) and abdominal pain (45%), while 26% had anemia. Although 27% of the individuals selected for validation had been informed about gluten-free diet, only 13% were adhering to a gluten-free diet at the end of follow-up.

Conclusion

Individuals with positive CD serology but normal mucosa often have CD-like symptoms and a family history of CD.