A practical approach to small bowel biopsy interpretation: celiac disease and its mimics

Eosinophil-mast cell pattern of intraepithelial infiltration as a marker of severity in CRSwNP

Chronic rhinosinusitis with nasal polyps (CRSwNP) is defined as a Type 2 eosinophilic disease, while CRSsNP is considered a Type 1 neutrophilic disease. Since neutrophils are also activated in eosinophilic CRSwNP, the eosinophil-neutrophil dualism has been revaluated. Among the inflammatory cells infiltrating sinus-nasal tissues, the role of mast cells (MCs) is not already recognized, although Clinical-Cytological Grading, which defines the severity of CRSwNP, attributes to mixed eosinophil-MC forms of CRSwNP a greater risk of recurrence. We aimed to examine nasal polyps from both a cytological and histopathological point of view, to evaluate the presence and localization of MCs. Cytological and histological examination of 39 samples of nasal polyps were performed. Immunohistochemistry was used to evaluate the presence of Tryptase + CD117 + MCs, which were counted both in the epithelial layer and in the lamina propria. A statistically significant correlation was found between intraepithelial MCs and CRSwNP severity (p < 0.001) and between the total eosinophil count and the total mast cell count (p < 0.001). Cytological examination and immunohistochemistry were comparable in detecting the presence of intraepithelial MCs (p = 0.002). The histological cut-off of 6 intraepithelial MCs was identified to detect severe CRSwNP (p < 0.001). MCs have been shown to be located in the lamina propria of almost all eosinophilic nasal polyps without significantly affecting their severity. Intraepithelial MCs are associated with greater severity of CRSwNP. Histopathological criteria of the eosinophil-MC form of CRSwNP in addition to the eosinophilic one, should be defined to guarantee patients effective and tailored treatments.

Co-factors, Microbes, and Immunogenetics in Celiac Disease to Guide Novel Approaches for Diagnosis and Treatment

Celiac disease (CeD) is a frequent immune-mediated disease that affects not only the small intestine but also many extraintestinal sites. The role of gluten proteins as dietary triggers, HLA-DQ2 or -DQ8 as major necessary genetic predisposition, and tissue transglutaminase (TG2) as mechanistically involved autoantigen, are unique features of CeD. Recent research implicates many cofactors working in synergism with these key triggers, including the intestinal microbiota and their metabolites, nongluten dietary triggers, intestinal barrier defects, novel immune cell phenotypes, and mediators and cytokines. In addition, apart from HLA-DQ2 and -DQ8, multiple and complex predisposing genetic factors and interactions have been defined, most of which overlap with predispositions in other, usually autoimmune, diseases that are linked to CeD. The resultant better understanding of CeD pathogenesis, and its manifold manifestations has already paved the way for novel therapeutic approaches beyond the lifelong strict gluten-free diet, which poses a burden to patients and often does not lead to complete mucosal healing. Thus, supported by improved mouse models for CeD and in vitro organoid cultures, several targeted therapies are in phase 2-3 clinical studies, such as highly effective gluten-degrading oral enzymes, inhibition of TG2, cytokine therapies, induction of tolerance to gluten ingestion, along with adjunctive and preventive approaches using beneficial probiotics and micronutrients. These developments are supported by novel noninvasive markers of CeD severity and activity that may be used as companion diagnostics, allow easy-to perform and reliable monitoring of patients, and finally support personalized therapy for CeD.

Giardia lamblia and Helicobacter pylori coinfection in gastrointestinal biopsies: A retrospective single-center analysis from Switzerland

BACKGROUND

The protozoan Giardia lamblia (GL) and the bacterium Helicobacter pylori (HP) are common causes of gastrointestinal disease. Coinfection is common and has been reported in studies from Africa, Europe, North America and Asia, but data for Switzerland are scarce.

AIM

To investigate GL and HP prevalence and coinfection rate in gastrointestinal biopsies from the Zurich area of Switzerland.

METHODS

Cases were retrieved from the laboratory information system (Medica Institute of Clinical Pathology, Zurich, Switzerland). Histological slides of cases with GL were reviewed, as were the concurrent gastric biopsies, where available.

RESULTS

Between January 1, 2013 and December 31, 2020, GL was found in 88 (0.14%) of 62,402 patients with a small intestine biopsy and HP in 10,668 (15.5%) of 68,961 patients with a gastric biopsy. 74/88 (84.1%) of patients with GL had unremarkable small intestine biopsies, 13/88 (14.8%) had increased intraepithelial lymphocytes, 5/88 (5.7%) showed villous atrophy and 2/88 (2.3%) acute inflammation. 71/88 patients (80.7%) with GL had an available gastric biopsy, of which 12/71 (16.9%) were unremarkable, 28/71 (39.4%) had HP-associated gastritis, 11/71 (15.5%) showed reactive gastropathy and 1/71 (1.4%) had autoimmune gastritis.

CONCLUSION

Coinfection with HP is common in patients with GL in gastrointestinal biopsies from the Zurich area of Switzerland. Therefore, gastroenterologists should consider sampling the stomach when GL is suspected for evaluation of possible concurrent HP-associated gastritis. Likewise, pathologists should scrutinize any small intestine biopsy for the presence of GL when HP-associated gastritis is seen, and vice versa.

Pediatric hematolymphoid pathology in the gastrointestinal tract

Hematolymphoid processes involving the gastrointestinal tract in the pediatric and adolescent young adult (AYA) populations include processes occurring primarily within the gastrointestinal tract as well as systemic diseases with predilection for gastrointestinal involvement. Here, we present a focused review of reactive and neoplastic entities occurring in the pediatric and AYA age groups.

Neuroendocrine Cells Are Commonly Absent in the Intestinal Crypts in Autoimmune Enteropathy

The absence of neuroendocrine (NE) cells in the intestinal mucosa in autoimmune enteropathy (AIE) has been occasionally reported. However, the status of NE cells has not been studied in detail in AIE. Small bowel and colonic biopsies were retrospectively retrieved from 18 AIE patients (26 baseline [18 small bowel and 8 colon]; and 15 follow-up [11 duodenum and 4 colon] biopsies in 11 patients). Thirty-three common variable immunodeficiency (CVID) patients (30 small bowel and 16 colon), 15 inflammatory bowel disease patients (5 duodenum and 10 colon), 13 immunoglobulinA deficiency patients (13 duodenum and 5 colon), and 10 normal controls (5 colon and 5 duodenum) were selected as control groups. Histologic features (villous atrophy, intraepithelial lymphocytosis, acute inflammation, crypt apoptosis, and absence or presence of goblet cells, Paneth cells and plasma cells) were recorded. Chromogranin immunostain was performed and chromogranin-positive NE cells were counted per 10 consecutive, well-oriented crypts. On the basis of the number of chromogranin-positive NE cells, cases were graded as being absent (≤3 NE cells), markedly decreased (≤15), and intact (>15). The NE cell status correlated with histologic features. The median age of 18 AIE patients was 38.5 years (range: 11 to 74 y) and 14 patients were male. Fourteen of 18 (78%) patients showed loss (absent or markedly decreased) of NE cells in the small bowel and/or colon in the baseline biopsies including 12 (of 18) small bowel and 6 (of 8) colon biopsies. Follow-up biopsy was available in 11 patients. Six of 7 (85%) patients who showed loss of NE cells in the baseline biopsies regained NE cells in the follow-up biopsies, and 1 patient continued to show loss of NE cells. Four patients who showed intact NE cells in the baseline remained unchanged in the follow-up. Among the control groups, 3 of 33 (9%) CVID patients showed loss of NE cells. NE cells were not lost in the biopsies of all 15 and 13 patients with inflammatory bowel disease and immunoglobulinA deficiency, respectively, or the 10 normal controls. In all 41 biopsies (26 baseline plus 15 follow-up) with AIE, NE cell loss was significantly associated with increased crypt apoptosis and loss of goblet cells (P=0.001, both) but not with other histologic findings. In conclusion, our study suggests that NE cells may also be the target cells in AIE and commonly lost in the intestinal crypts in AIE, and consequently loss of NE cells can be used as an adjunct histologic feature for diagnosis of AIE.

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.

The role of small intestinal bacterial overgrowth and false positive diagnosis of lactose intolerance in southwest Hungary-A retrospective observational study

Background

Lactose intolerance is a frequent gastrointestinal disease affecting 47% of the Eastern European population. Small intestinal bacterial overgrowth (SIBO) leads to carbohydrate malabsorption and therefore to false results during lactose breath and tolerance tests.

Objectives

We aimed to assess the prevalence of lactose maldigestion and intolerance in Hungary and to investigate the role of combined diagnostic method and testing for SIBO in reducing false results.

Methods

We retrospectively analyzed data from 264 adult symptomatic patients who underwent 50g lactose breath and tolerance tests in parallel over a one-year period at our center. A ≥20 ppm elevation of H₂ or less than 1.1 mmol/l rise of blood glucose was diagnostic for lactose maldigestion. Patients with maldigestion who had symptoms during the test were defined as lactose intolerant. Patients with an early (≤90 min) significant (≥20 ppm) rise of H₂ during lactose and/or lactulose breath tests were determined to have SIBO. Patients with slow/rapid oro-cecal transit and inappropriate preparation before the test were excluded.

Results

49.6% of the 264 patients had lactose maldigestion, and 29.5% had lactose intolerance. The most frequent symptom was bloating (22.7%), while 34.8% of the study population and 60% of the symptomatic patients had SIBO. In 9.1% and 9.8% of the patients, the lactose breath and tolerance test alone gave false positive result compared with the combined method. SIBO was present in 75% of the false positives diagnosed with breath test only.

Conclusions

The prevalence of lactose intolerance is lower in Hungary compared to the Eastern European value (29.5% vs 47%), so it is worth performing a population-based prospective analysis in this area. A combination of lactose breath and tolerance tests and the careful monitoring of results (with early H2 rise, lactulose breath test, etc.) can decrease the false cases caused by e.g. SIBO.

Educational Case: Immune-Related Disorders of the Bowel: Celiac Disease

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.

Microbes and Viruses Are Bugging the Gut in Celiac Disease. Are They Friends or Foes?

The links between microorganisms/viruses and autoimmunity are complex and multidirectional. A huge number of studies demonstrated the triggering impact of microbes and viruses as the major environmental factors on the autoimmune and inflammatory diseases. However, growing evidences suggest that infectious agents can also play a protective role or even abrogate these processes. This protective crosstalk between microbes/viruses and us might represent a mutual beneficial equilibrium relationship between two cohabiting ecosystems. The protective pathways might involve post-translational modification of proteins, decreased intestinal permeability, Th1 to Th2 immune shift, induction of apoptosis, auto-aggressive cells relocation from the target organ, immunosuppressive extracellular vesicles and down regulation of auto-reactive cells by the microbial derived proteins. Our analysis demonstrates that the interaction of the microorganisms/viruses and celiac disease (CD) is always a set of multidirectional processes. A deeper inquiry into the CD interplay with Herpes viruses and Helicobacter pylori demonstrates that the role of these infections, suggested to be potential CD protectors, is not as controversial as for the other infectious agents. The outcome of these interactions might be due to a balance between these multidirectional processes.

Intraepithelial lymphocytes, scores, mimickers and challenges in diagnosing gluten-sensitive enteropathy (celiac disease)

The upper digestive tract is routinely scoped for several causes of malabsorption, and the number of duodenal biopsy specimens has increased notably in the last 10 years. Gluten-sensitive enteropathy (GSE) is an autoimmune disease, which shows an increasing prevalence worldwide and requires a joint clinico-pathological approach. The classical histopathology of GSE with partial or total villous blunting is well recognized, but the classification of GSE is not straightforward. Moreover, several mimickers of GSE with intraepithelial lymphocytosis have been identified in the last 20 years, with drug interactions and medical comorbidities adding to the conundrum. In this review, we report on the normal duodenal mucosa, the clinical presentation and laboratory diagnosis of GSE, the duodenal intraepithelial lymphocytes and immunophenotype of GSE-associated lymphocytes, the GSE mimickers, the differences "across oceans" among guidelines in diagnosing GSE, and the use of a synoptic report for reporting duodenal biopsies in both children and adults in the 21st century.

Assessment of intestinal malabsorption

Significant efforts have been made in the last decade to either standardize the available tests for intestinal malabsorption or to develop new, more simple and reliable techniques. The quest is still on and, unfortunately, clinical practice has not dramatically changed. The investigation of intestinal malabsorption is directed by the patient's history and baseline tests. Endoscopy and small bowel biopsies play a major role although non-invasive tests are favored and often performed early on the diagnostic algorithm, especially in paediatric and fragile elderly patients. The current clinically available methods and research tools are summarized in this review article.

Promoting intestinal adaptation by nutrition and medication

The ultimate goal in the treatment of short bowel syndrome is to wean patients off parenteral nutrition, by promoting intestinal adaptation. Intestinal adaptation is the natural compensatory process that occurs after small bowel resection. Stimulating the remaining bowel with enteral nutrition can enhance this process. Additionally, medication can be used to either reduce factors that complicate the adaptation process or to stimulate intestinal adaptation, such as antisecretory drugs and several growth factors. The aim of this review was to provide an overview of the best nutritional strategies and medication that best promote intestinal adaptation.

Olmesartan-Associated Enteropathy: A Review of Clinical and Histologic Findings

Olmesartan is an antihypertensive medication belonging to the angiotensin II receptor blocker class of drugs that has recently been associated with severe enteropathy. Olmesartan-associated enteropathy is uncommon and may be difficult to recognize because of its clinical and histologic similarities to other clinical entities, including celiac sprue and autoimmune enteropathy. The purpose of this article is to review the clinical and histologic findings of olmesartan-associated enteropathy that have been reported in the literature and to discuss clinical entities to consider in the differential diagnosis of olmesartan-associated enteropathy.