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

Human organoids with an autologous tissue-resident immune compartment

The intimate relationship between the epithelium and immune system is crucial for maintaining tissue homeostasis, with perturbations therein linked to autoimmune disease and cancer1-3. Whereas stem cell-derived organoids are powerful models of epithelial function4, they lack tissue-resident immune cells that are essential for capturing organ-level processes. We describe human intestinal immuno-organoids (IIOs), formed through self-organization of epithelial organoids and autologous tissue-resident memory T (TRM) cells, a portion of which integrate within the epithelium and continuously survey the barrier. TRM cell migration and interaction with epithelial cells was orchestrated by TRM cell-enriched transcriptomic programs governing cell motility and adhesion. We combined IIOs and single-cell transcriptomics to investigate intestinal inflammation triggered by cancer-targeting biologics in patients. Inflammation was associated with the emergence of an activated population of CD8+ T cells that progressively acquired intraepithelial and cytotoxic features. The appearance of this effector population was preceded and potentiated by a T helper-1-like CD4+ population, which initially produced cytokines and subsequently became cytotoxic itself. As a system amenable to direct perturbation, IIOs allowed us to identify the Rho pathway as a new target for mitigation of immunotherapy-associated intestinal inflammation. Given that they recapitulate both the phenotypic outcomes and underlying interlineage immune interactions, IIOs can be used to study tissue-resident immune responses in the context of tumorigenesis and infectious and autoimmune diseases.

Clinicopathologic Analysis of Malabsorption Syndrome in a Tertiary Care Center in South India

Background:

Malabsorption syndrome is an umbrella term for manifestations consisting of diarrhea, steatorrhea, malnutrition, unexplained weight loss, persistent or recurrent abdominal pain, and anemia. Celiac disease and Tropical sprue remain the two important causes among many more.

Materials and Methods:

The objectives of this study were to assess the spectrum of histological features of malabsorption at a tertiary care center and to correlate the clinical, endoscopic, and histological features between the various etiologies. Biopsy specimens of 547 subjects formed the sample for this institutional-based, retrospective research. All subjects who had a clinical diagnosis of malabsorption and underwent subsequent endoscopic evaluation along with biopsy were considered. The hematoxylin and eosin-stained sections were analyzed for villous architecture and intraepithelial lymphocytes (IELs). The histopathological findings were further correlated with the endoscopic findings. Data thus obtained were statistically analyzed using Microsoft Excel for Windows (2010).

Results:

The mean age of the subjects was 46.65 ± 17.31 years and with 330 males (60.33%) and 217 female (39.63%) subjects. Chronic diarrhea was the major presenting symptom in 95% of the subjects (n = 520). Normal villous architecture was noted in 68.19%, while the remaining cases showed varying degrees of atrophy ranging from mild in 27.61% (n = 151) to moderate in 2.56% (n = 14) to severe in 1.65% (n = 9). IELs were noted in 70.78% of cases.

Conclusion:

Histopathological findings, when analyzed, showed intraepithelial lymphocytosis as the major diagnosis in 34.19% of cases (n = 187), followed by tropical sprue in 19.56% (n = 107) cases. The pathology was nonspecific in about 13.89% (n = 76).

Review article: Becoming and being coeliac-special considerations for childhood, adolescence and beyond

Classically considered a disease of early childhood characterised by malabsorption and failure to thrive, coeliac disease is now recognised to arise in genetically susceptible individuals at any age. Although permissive HLA genotypes are the strongest predictor of coeliac disease, they are not sufficient. Several prospective cohort studies enrolling genetically at-risk infants have investigated the role of potential triggers of coeliac disease autoimmunity, such as timing of gluten introduction, viral infections and dietary patterns. Much less is known about triggers of coeliac disease in adulthood. Better understanding of factors leading to coeliac disease may be helpful in the management of those with potential coeliac disease (elevated serum celiac antibodies without villous atrophy in the small intestine), many of whom initiate a gluten-free diet without demonstration of villous atrophy. There are a range of clinical presentations of celiac disease in childhood and patterns of coeliac serology, including fluctuation and spontaneous reversion on a gluten-containing diet, vary. There is a current debate over best strategies to manage adults and children with potential coeliac disease to avoid over-treatment and under-treatment. Childhood and adolescence carry unique issues pertaining to the diagnosis and management of coeliac disease, and include nutrition and growth, rescreening, repeat biopsy, dietary adherence concerns and transition to adult care. In conclusion, while coeliac disease has similar pathogenesis and general clinical manifestations in paediatric and adult populations, diagnostic and management approaches need to adapt to the developmental stages.

The Effects of Colchicine on the Histopathological Findings of Celiac Disease During Familial Mediterranean Fever Treatment

Familial mediterranean fever (FMF) and Celiac Disease (CD) are both autoinflammatory and autoimmune diseases with common clinical features affecting the gastrointestinal system. Familial mediterranean fever may coexist with CD. Inflammatory cells and cytokines are up-regulated within the intestinal mucosa of patients with CD. In this perspective, lymphocyte infiltration to the lamina propria of the small intestinal mucosa is a critical pathological sign. In the present study, we aimed to find out whether the treatment of an FMF patient with colchicine affects the pathological signs of concomitant developed CD on the same patient. We retrospectively reviewed the medical records of 147 patients with FMF who were followed up in our center between 2015 and 2020. Of the 147 patients with FMF, 3 patients also had CD. In this report, we presented these 3 cases. The findings obtained in this study suggest that pathological findings may be misinterpreted in autoimmune diseases, such as CD, when patients administer anti-inflammatory treatments, such as colchicine.

A New Target Organ of Leishmania (Viannia) braziliensis Chronic Infection: The Intestine

Leishmania (Viannia) braziliensis is one of the main causes of cutaneous leishmaniasis in the Americas. This species presents genetic polymorphism that can cause destructive lesions in oral, nasal, and oropharyngeal tracts. In a previous study, the parasite caused several histopathological changes to hamster ileums. Our study evaluates immune response components, morphological changes, and effects on neurons in the ileums of hamsters infected by three different strains of L. (V.) braziliensis in two infection periods. For the experiment, we separated hamsters into four groups: a control group and three infected groups. Infected hamsters were euthanized 90- or 120-days post infection. We used three strains of L. (V.) braziliensis: the reference MHOM/BR/1975/M2903 and two strains isolated from patients who had different responses to Glucantime^® treatment (MHOM/BR/2003/2314 and MHOM/BR/2000/1655). After laparotomy, ileums were collected for histological processing, biochemical analysis, and evaluation of neurons in the myenteric and submucosal plexuses of the enteric nervous system (ENS). The results demonstrated the increase of blood leukocytes after the infection. Optical microscopy analysis showed histopathological changes with inflammatory infiltrates, edemas, ganglionitis, and Leishmania amastigotes in the ileums of infected hamsters. We observed changes in the organ histoarchitecture of infected hamsters when compared to control groups, such as thicker muscular and submucosa layers, deeper and wider crypts, and taller and broader villi. The number of intraepithelial lymphocytes and TGF-β-immunoreactive cells increased in all infected groups when compared to the control groups. Mast cells increased with longer infection periods. The infection also caused remodeling of intestinal collagen and morphometry of myenteric and submucosal plexus neurons; but this effect was dependent on infection duration. Our results show that L. (V.) braziliensis infection caused time-dependent alterations in hamster ileums. This was demonstrated by the reduction of inflammatory cells and the increase of tissue regeneration factors at 120 days of infection. The infected groups demonstrated different profiles in organ histoarchitecture, migration of immune cells, and morphometry of ENS neurons. These findings suggest that the small intestine (or at least the ileum) is a target organ for L. (V.) braziliensis infection, as the infection caused changes that were dependent on duration and strain.

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.

Vitamin D and Primary Ciliary Dyskinesia: A Topic to Be Further Explored

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by abnormalities in ciliary structure/function. The diagnosis of PCD relies on a combination of clinical evaluation and ultrastructural (electron microscopic) analysis of the ciliary architecture. This diagnosis may be challenging due to clinical and genetic heterogeneity and artifacts during the ciliary ultrastructure preparation and assessment. Recently, vitamin D supplementation has been proposed for several groups probably suffering from D-hypovitaminosis. Some patients with inflammatory bowel disease may have significant malabsorption, and vitamin D supplementation in these patients is recommended. Two recent reports suggest that a low plasmatic level of this vitamin is present in the PCD population. The utility of vitamin D supplementation may be essential in this group of individuals, and further investigations are warranted. Still, in examining the literature papers, it seems relevant that the authors concentrate solely on lung function in both studies. Future studies should probably target the intestinal function in patients with PCD independently from the vitamin D supplementation to fully evaluate its role.

Progression of pediatric celiac disease from potential celiac disease to celiac disease: a retrospective cohort study

Background

A subset of patients with serology suggesting celiac disease have an initially negative biopsy but subsequently develop histopathologic celiac disease. Here we characterize patients with potential celiac disease who progress to celiac disease.

Methods

We performed a retrospective analysis of children (0–18 years of age) with biopsy-confirmed celiac disease seen at St. Louis Children’s Hospital between 2013 and 2018.

Results

Three hundred sixteen of 327 (96%) children with biopsy-confirmed celiac disease were diagnosed on initial biopsy. The 11 children with potential celiac disease who progressed to celiac disease had lower anti-tissue transglutaminase (anti-TTG IgA) concentrations (2.4 (1.6–5) X upper limit of normal (ULN) vs. 6.41 (3.4–10.5) X ULN) at time of first biopsy. Their median anti-TTG IgA concentrations rose from 2.4 (1.6–5) X ULN to 3.6 (3.1–9.2) X ULN between biopsies.

Conclusions

Four percent of biopsy confirmed celiac patients initially had a negative biopsy, but later developed histopathologic celiac disease. This is likely an underestimate as no surveillance algorithm was in place. We recommend repeat assessment in children whose serology suggests celiac disease despite normal small bowel biopsy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02625-z.

Non-celiac wheat sensitivity: rationality and irrationality of a gluten-free diet in individuals affected with non-celiac disease: a review

Non-celiac gluten or wheat sensitivity (NCWS) is a "clinical entity induced by the ingestion of wheat leading to intestinal and/or extraintestinal symptoms that improve once the wheat-containing foodstuff is removed from the diet, and celiac disease and wheat allergy have been excluded". This mostly accepted definition raises several points that remain controversial on this condition. In the present review, the authors summarize the most recent advances in the clinic and research on NCWS through an accurate analysis of different studies. We screened PubMed, Medline, Embase, and Scopus using the keywords "non-celiac gluten sensitivity", "non-celiac wheat sensitivity", and "diagnosis". We would like to emphasize two main points, including (A) the controversial clinical and etiological aspects in different trials and experiences with particular attention to the Salerno criteria for the diagnosis of NCWS and (B) the histological aspects. The etiology of NCWS remains controversial, and the relationship with irritable bowel syndrome is obscure. Histologically, the duodenal mucosa may show a variable pattern from unremarkable to a slight increase in the number of T lymphocytes in the superficial epithelium of villi. The endorsement of this disease is based on a positive response to a gluten-free diet for a limited period, followed by the reappearance of symptoms after gluten challenge. The Salerno expert criteria may help to diagnose NCWS accurately. Social media and inaccurate interpretation of websites may jeopardize the diagnostic process if individuals self-label as gluten intolerant.

Effects of Helicobacter Pylori Infection on Serology and Intestinal Mucosal Changes in Pediatric Patients With Celiac Disease: A Retrospective Cohort Study

Introduction Helicobacter pylori (HP) and celiac disease (CD) can cause similar mucosal damage to the duodenal mucosa. For this reason, the relationship between these two diseases has been the subject of research recently. Our study aims to investigate the effects of HP infection on serology and pathology in pediatric patients with CD or potential celiac disease (PCD). Methods It is a retrospective cohort study conducted in the third-level education and research hospital between July 2017 and May 2019. The serological and pathological data of patients diagnosed with CD or PCD were compared statistically according to the presence of HP. Results An analysis of the histopathological data of the endoscopic biopsy samples showed Helicobacter pylori in eight (50%) of PCD patients and 37 (41.6%) of CD patients. No significant difference was found between the two groups (P=0.531). We found that dokutransglutaminas antibody level (DTG) and endomysium antibody level (EMA) serology decreased significantly after HP eradication therapy in HP (+) PCD (P=0.002, P<0.001). Intestinal metaplasia was not present in PCH. However, intestinal metaplasia was present in five patients (13.5%) with HP (+) CD and two patients (3.8%) with HP (-) CD. However, that difference was not statistically significant between the two groups (P=0.095). Conclusion Our study demonstrated that HP may augment CD's serology and serological improvement is possible after HP treatment particularly in HP (+) PCD. Therefore, we recommend re-perform diagnostic studies after HP treatment before commencing a gluten-free diet in HP (+) suspected CD cases.

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.

Serum Level and Gene Expression of Interleukin-15 Do Not Correlate with Villous Atrophy in Celiac Disease Patients

Background and Aims: Interleukin-15 (IL-15) is a key player in the pathogenesis of celiac disease (CD). We investigated the functional role of IL-15 in the process of epithelial cell phenotypic modification at different stages of CD. Materials and Methods: In this study, we looked for correlations between the IL-15 mRNA levels in duodenal tissue and serum protein levels in a cohort of Iranian patients affected by CD based on the degree of histopathology. Ninety-five formalin-fixed, paraffin-embedded duodenal tissue specimens were collected: 23 with a Marsh I value; 30 with a Marsh II value; 32 with a Marsh III value; and 10 normal controls. The expression levels of the IL-15 gene in these biopsy specimens were determined by real-time quantitative polymerase chain reaction (qPCR), and IL-15 serum protein concentrations were determined by enzyme-linked immunosorbent assay and compared to tissue expression. Results: The IL-15 mRNA levels were higher in patients with Marsh II compared with the control group, and the Marsh I, and Marsh III groups. The differences between the Marsh II and Marsh I patients were statistically significant (p = 0.03). Similarly, the serum concentration of IL-15 was higher in Marsh II patients compared to those with Marsh I and Marsh III lesions, although the differences were not statistically significant (p = 0.221). Conclusions: Our results demonstrate that IL-15 gene expression might be elevated only in the early stages of CD onset (and histological damage) and that IL-15 serum levels do not significantly correlate with its tissue expression whatever the degree of histopathology.

The methylome of the celiac intestinal epithelium harbours genotype-independent alterations in the HLA region

The Human Leucocyte Antigen (HLA) locus and other DNA sequence variants identified in Genome-Wide Association (GWA) studies explain around 50% of the heritability of celiac disease (CD). However, the pathogenesis of CD could be driven by other layers of genomic information independent from sequence variation, such as DNA methylation, and it is possible that allele-specific methylation explains part of the SNP associations. Since the DNA methylation landscape is expected to be different among cell types, we analyzed the methylome of the epithelial and immune cell populations of duodenal biopsies in CD patients and controls separately. We found a cell type-specific methylation signature that includes genes mapping to the HLA region, namely TAP1 and HLA-B. We also performed Immunochip SNP genotyping of the same samples and interrogated the expression of some of the affected genes. Our analysis revealed that the epithelial methylome is characterized by the loss of CpG island (CGI) boundaries, often associated to altered gene expression, and by the increased variability of the methylation across the samples. The overlap between differentially methylated positions (DMPs) and CD-associated SNPs or variants contributing to methylation quantitative trait loci (mQTLs) is minimal. In contrast, there is a notable enrichment of mQTLs among the most significant CD-associated SNPs. Our results support the notion that DNA methylation alterations constitute a genotype-independent event and confirm its role in the HLA region (apart from the well-known, DQ allele-specific effect). Finally, we find that a fraction of the CD-associated variants could exert its phenotypic effect through DNA methylation.

Prevalence of markers of celiac disease in Colombian children with diabetes mellitus type 1

Introduction:

Although the association between diabetes mellitus type 1 (T1DM) and celiac disease (CD) is well established; there are only a few studies that focus on South American children, haplotypes and their possible associations.

Objective:

To determine the prevalence of CD markers in a group of children with T1DM and to analyze the associated clinical, immunological and genetic manifestations.

Methods:

A prevalence study focusing on children with T1DM who were assessed based on variables including sociodemographics, anthropometric information, disease characteristics, laboratory results and family medical history. In partitipants a positive tTG2 (Ig A anti-transglutaminase), a duodenal biopsy and genotype were performed. The proportion of children with T1DM and CD was estimated (CI 95%). Determinations of central tendency, univariate and bivariate analysis, were also performed; p <0.05 was considered significant.

Results:

Thirteen (8.4%) of the 155 children (53.6% girls, 11.0 ±3.6 years, 2-18 years) with T1DM were tTG2 positive, four had CD (2.6%), seven had potential CD (4.5%) and nine were HLA DQ2/DQ8 positive (5.8%). Children with T1DM and CD had their last ketoacidotic episode (21.5 ±30.4 months versus 69.5 ±38.8 months, p= 0.0260) earlier than children with T1DM and potential CD. There were no differences with anthropometry or with the laboratory results regarding glycemic control.

Conclusions:

The prevalence of CD in these children with T1DM is higher than that reported in other South American countries. The prevalence of CD was found to be associated with the time of presentation of T1DM and its main allele, the DQ2/DQ8. These findings are different from what has been described in other places around the world.

Prevalence of markers of celiac disease in Colombian children with diabetes mellitus type 1

Introduction: Although the association between diabetes mellitus type 1 (T1DM) and celiac disease (CD) is well established; there are only a few studies that focus on South American children, haplotypes and their possible associations. Objective: To determine the prevalence of CD markers in a group of children with T1DM and to analyze the associated clinical, immunological and genetic manifestations. Methods: A prevalence study focusing on children with T1DM who were assessed based on variables including sociodemographics, anthropometric information, disease characteristics, laboratory results and family medical history. In partitipants a positive tTG2 (Ig A anti-transglutaminase), a duodenal biopsy and genotype were performed. The proportion of children with T1DM and CD was estimated (CI 95%). Determinations of central tendency, univariate and bivariate analysis, were also performed; p <0.05 was considered significant. Results: Thirteen (8.4%) of the 155 children (53.6% girls, 11.0 ±3.6 years, 2-18 years) with T1DM were tTG2 positive, four had CD (2.6%), seven had potential CD (4.5%) and nine were HLA DQ2/DQ8 positive (5.8%). Children with T1DM and CD had their last ketoacidotic episode (21.5 ±30.4 months versus 69.5 ±38.8 months, p= 0.0260) earlier than children with T1DM and potential CD. There were no differences with anthropometry or with the laboratory results regarding glycemic control. Conclusions: The prevalence of CD in these children with T1DM is higher than that reported in other South American countries. The prevalence of CD was found to be associated with the time of presentation of T1DM and its main allele, the DQ2/DQ8. These findings are different from what has been described in other places around the world.

Bactibilia in women affected with diseases of the biliary tract and pancreas. A STROBE guidelines-adherent cross-sectional study in Southern Italy

PURPOSE

Bile is a hepatobiliary lipid-rich sterile solution, and its colonization by microorganisms defines the condition of bactibilia. In this study, we aimed to assess the bile microbiological flora and its potential link with comorbidity in women.

METHODOLOGY

We performed a microbiologic investigation on 53 female patients with biliopancreatic diseases who granted consent, and we analysed the data using a MATLAB platform.

RESULTS

We found that the most frequent disease associated with bactibilia was pancreas head carcinoma (PHC) (P=0.0015), while the least frequent disease was gall bladder carcinoma (GBC) (P=0.0002). The most common microorganisms were Pseudomonas spp. (P<0.0001) and Escherichia coli (P<0.0001). In particular Pseudomonas spp. and E. coli were negatively correlated to PHC presence and positively correlated to CCA by both univariate and multivariate analysis.

CONCLUSIONS

Gram-negative bacteria have been linked to a tumour-associated inflammatory status. In the last 30 years, the analysis of mortality rate in Italy for PHC and GBC shows an increasing and a decreasing trend, respectively. Although this study targeted only 53 patients and does not reflect the frequency of diagnosis in a Southern Italian population, the decrease in GBC may raise the suggestion ofnon-adherence to a Mediterranean diet that may have become more prevalent in Southern Italy since the 1990s.

All disease begins in the gut: Influence of gastrointestinal disorders and surgery on oral drug performance

The term "disease" conjures a plethora of graphic imagery for many, and the use of drugs to combat symptoms and treat underlying pathology is at the core of modern medicine. However, the effects of the various gastrointestinal diseases, infections, co-morbidities and the impact of gastrointestinal surgery on the pharmacokinetic and pharmacodynamic behaviour of drugs have been largely overlooked. The better elucidation of disease pathology and the role of underlying cellular and molecular mechanisms have increased our knowledge as far as diagnoses and prognoses are concerned. In addition, the recent advances in our understanding of the intestinal microbiome have linked the composition and function of gut microbiota to disease predisposition and development. This knowledge, however, applies less so in the context of drug absorption and distribution for orally administered dosage forms. Here, we revisit and re-evaluate the influence of a portfolio of gastrointestinal diseases and surgical effects on the functionality of the gastrointestinal tract, their implications for drug delivery and attempt to uncover significant links for clinical practice.

Intestinal epithelium, intraepithelial lymphocytes and the gut microbiota - Key players in the pathogenesis of celiac disease

Celiac disease (CD) is a chronic immune-mediated disorder triggered by the ingestion of gluten in genetically predisposed individuals. Before activating the immune system, gluten peptides are transferred by the epithelial barrier to the mucosal lamina propria, where they are deamidated by intestinal tissue transglutaminase 2. As a result, they strongly bind to human leucocyte antigens (HLAs), especially HLA-DQ2 and HLA-DQ8, expressed on antigen-presenting cells. This induces an inflammatory response, which results in small bowel enteropathy. Although gluten is the main external trigger activating both innate and adaptive (specific) immunity, its presence in the intestinal lumen does not fully explain CD pathogenesis. It has been hypothesized that an early disruption of the gut barrier in genetically susceptible individuals, which would result in an increased intestinal permeability, could precede the onset of gluten-induced immune events. The intestinal barrier is a complex functional structure, whose functioning is dependent on intestinal microbiota homeostasis, epithelial layer integrity, and the gut-associated lymphoid tissue with its intraepithelial lymphocytes (IELs). The aim of this paper was to review the current literature and summarize the role of the gut microbiota, epithelial cells and their intercellular junctions, and IELs in CD development.

Intraepithelial lymphocyte immunophenotype: a useful tool in the diagnosis of celiac disease

According to new ESPGHAN guidelines, gluten challenge is considered necessary when there is doubt about the initial diagnosis of celiac disease (CD). The main aim of this study was to quantify intraepithelial lymphocyte (IEL) immunophenotype on celiac patients on gluten-containing diet (GCD) compared to those on gluten-free diet (GFD). Another aim was to evaluate the clinical utility of IELs in the CD diagnosis, especially in selected patients on GFD where diagnostic uncertainty remains. IEL immunophenotype (TCRγδ and NK-like IELs) were studied by flow cytometry in 111 children with CD (81 children with CD on GCD and 30 celiac patients on GFD) and a control group (10 children). Duration of GFD was 5.4 ± 1.6 years. TCRγδ IELs in celiac patients receiving a GCD or GFD were significantly higher (p < 0.001) than in the control group. NK-like IELs in patients receiving a GCD or GFD were significantly lower than in the control group (p < 0.001). We observed a permanent decrease of NK-like IELs and an increment of TCRγδ IELs after following an adequate establishment and compliance of a long-term GFD in celiac patients. Recognition of IELs changes in the intestinal mucosa on celiac patients after long-term establishment of a GFD could constitute a useful tool for CD diagnosis in various situations: in which there is doubt about the initial diagnosis and repeat biopsy is necessary (avoiding the need of gluten challenges), and in those patients with symptoms/signs suggestive of CD who maintain a low gluten diet.