Exploring Total Immunoglobulin A's Impact on Non-Biopsy Diagnosis of Celiac Disease: Implications for Diagnostic Accuracy.

OBJECTIVE: In the current debate surrounding the biopsy-free diagnosis of CeD, it is crucial to identify factors influencing the accuracy of results. This study investigated the impact of total IgA on the non-invasive diagnosis of celiac disease (CeD). METHODS: We retrospectively assessed total IgA titers' influence on the diagnostic accuracy of different tTG-IgA thresholds compared to the upper reference value (UNL). RESULTS: Of 165 included patients, tTG-IgA values at 10× UNL and 6× UNL showed specificity of 82.6% and 73.9% and sensitivity of 49.3% and 69.0%, respectively, in predicting intestinal villous atrophy (Marsh 3). In 130 patients, total IgA levels were known at baseline. These patients were divided into three tertiles according to total IgA, i.e., patients with lower, intermediate, or higher total IgA within the population. For patients with total IgA ≥ 245 mg/dL, using a tTG-IgA cutoff of 6× UNL instead of 10× UNL resulted in decreased specificity from 71.4% to 42.8% and increased sensitivity from 67.6% to 81.1%. For patients with total IgA < 174 mg/dL and between 174 mg/dL and 245 mg/dL, using a tTG-IgA cutoff of 6× UNL instead of 10× UNL maintained specificity (75.0% and 85.7%, respectively) with increased sensitivity (from 46.2% to 64.1% and from 36.1% to 52.8%, respectively). CONCLUSIONS: In conclusion, total IgA influences the diagnostic accuracy of a predetermined tTG-IgA cutoff. Greater consideration should be given to total IgA, beyond its deficiency, in evaluating the applicability and accuracy of non-invasive CeD diagnosis.

Digesting gluten with oral endopeptidases to improve the management of celiac disease.

In our editorial, we want to comment on the article by Stefanolo et al titled "Effect of Aspergillus niger prolyl endopeptidase in patients with celiac disease on a long-term gluten-free diet". Celiac disease is an immune-mediated disorder triggered by dietary gluten in genetically predisposed individuals. Although avoiding gluten can permit patients to live symptom-free, ongoing voluntary or involuntary exposure to gluten is common and associated with persistent villous atrophy in small bowel mucosa. As villous atrophy predisposes patients to life threatening complications, such as osteoporotic fractures or malignancies, therapeutic adjuncts to gluten-free diet become important to improve patients' quality of life and, if these adjuncts can be shown to improve villous atrophy, avoid complications. Oral administration of enzyme preparations, such as endopeptidases that digest gluten and mitigate its antigenicity to trigger inflammation, is one clinical strategy under investigation. The article is about the utility of one endopeptidase isolated from Aspergillus niger. We critique findings of this clinical trial and also summarize endopeptidase-based as well as other strategies and how they can complement gluten-free diet in the management of celiac disease.

Diagnosis and resolution of olmesartan-associated sprue-like enteropathy confirmed by capsule endoscopy: a case report and literature review.

Herein, we describe a case of olmesartan-associated sprue-like enteropathy, in which improvement in villous atrophy was confirmed using small bowel capsule endoscopy. The patient was a 69-year-old woman who had persistent watery diarrhea (20 bowel movements/day) for 1 year and experienced a weight loss of 10 kg in the same period. Abdominal computed tomography revealed no abnormalities, and blood test results revealed no inflammatory reactions. Upper endoscopy and colonoscopy revealed villous atrophy in the duodenum and terminal ileum. As the patient was administered olmesartan for a long time and capsule endoscopy showed villous atrophy throughout the small bowel, she was diagnosed with olmesartan-associated sprue-like disease. Following the discontinuation of the medication, symptoms of diarrhea soon improved, and repeat capsule endoscopy indicated improvement in small intestinal villous atrophy. Olmesartan-associated sprue-like enteropathy should be considered a differential diagnosis in patients with severe chronic watery diarrhea. Our report is the first in which capsule endoscopy was performed multiple times over a long period for follow-up observation of improvements in the small intestine. In addition, our literature review regarding capsule endoscopy for olmesartan-associated enteritis might aid clinicians in the early diagnosis of the condition and the assessment of treatment efficacy.

New Insights on Genes, Gluten, and Immunopathogenesis of Celiac Disease.

Celiac disease (CeD) is a gluten-induced enteropathy that develops in genetically susceptible individuals upon consumption of cereal gluten proteins. It is a unique and complex immune disorder to study as the driving antigen is known and the tissue targeted by the immune reaction can be interrogated. This review integrates findings gained from genetic, biochemical, and immunologic studies, which together have revealed mechanisms of gluten peptide modification and HLA binding, thereby enabling a maladapted anti-gluten immune response. Observations in human samples combined with experimental mouse models have revealed that the gluten-induced immune response involves CD4+ T cells, cytotoxic CD8+ T cells, and B cells; their cross-talks are critical for the tissue-damaging response. The emergence of high-throughput technologies is increasing our understanding of the phenotype, location, and presumably function of the gluten-specific cells, which are all required to identify novel therapeutic targets and strategies for CeD.

IL-10-producing regulatory cells impact on celiac disease evolution.

Celiac Disease (CD) is a T-cell mediated disorder caused by immune response to gluten, although the mechanisms underlying CD progression are still elusive. We analyzed immune cell composition, plasma cytokines, and gliadin-specific T-cell responses in patients with positive serology and normal intestinal mucosa (potential-CD) or villous atrophy (acute-CD), and after gluten-free diet (GFD). We found: an inflammatory signature and the presence of circulating gliadin-specific IFN-γ+ T cells in CD patients regardless of mucosal damage; an increased frequency of IL-10-secreting dendritic cells (DC-10) in the gut and of circulating gliadin-specific IL-10-secreting T cells in potential-CD; IL-10 inhibition increased IFN-γ secretion by gliadin-specific intestinal T cells from acute- and potential-CD. On GFD, inflammatory cytokines normalized, while IL-10-producing T cells accumulated in the gut. We show that IL-10-producing cells are fundamental in controlling pathological T-cell responses to gluten: DC-10 protect the intestinal mucosa from damage and represent a marker of potential-CD.

Impact of delay in the diagnosis on the severity of celiac disease.

BACKGROUND AND AIM: Celiac disease (CeD) has now become a global disease with a worldwide prevalence of 0.67%. Despite being a common disease, CeD is often not diagnosed and there is a significant delay in its diagnosis. We reviewed the impact of the delay in the diagnosis on the severity of manifestations of CeD. METHODS: We reviewed clinical records of 726 consecutive patients with CeD from the Celiac Clinic database and the National Celiac Disease Consortium database. We extracted specific data including the demographics, symptoms at presentation, time of onset of symptoms, time to diagnosis from the onset of the symptoms, and relevant clinical data including fold-rise in anti-tissue transglutaminase antibody (IgA anti-tTG Ab) and severity of villous and crypt abnormalities as assessed using modified Marsh classification. RESULTS: The median duration between the onset of symptoms and the diagnosis of CeD was 27 months (interquartile range 12-60 months). A longer delay in the diagnosis of CeD from the onset of symptoms was associated with lower height for age, lower hemoglobin, higher fold rise in IgA Anti tTG titers, and higher severity of villous and crypt abnormalities. About 18% of patients presented with predominantly non-gastrointestinal complaints and had a longer delay in the diagnosis of CeD. CONCLUSIONS: There is a significant delay in the diagnosis of CeD since the onset of its symptoms. The severity of celiac disease increases with increasing delay in its diagnosis. There is a need to keep a low threshold for the diagnosis of CeD in appropriate clinical settings.

Flow cytometry for the assessment and monitoring of aberrant intraepithelial lymphocytes in non-responsive celiac disease and non-celiac enteropathies.

BACKGROUND: Few data are available on flow cytometry (FC) for monitoring intraepithelial lymphocytes (IELs) in refractory celiac disease (RCD), non-responsive celiac disease (NRCD), and non-celiac enteropathies (NCEs). AIMS: 1) To investigate the significance of monitoring IELs immunophenotype with FC in patients with NRCD, RCD and NCEs; 2) to evaluate FC concordance with immunohistochemistry (IHC) and γ-TCR clonality analysis. METHODS: Patients investigated between January-2012 and February-2023 were divided into two groups: 1)confirmed RCD or NRCD being investigated for persistent symptoms and suspected complications of celiac disease (CD); 2)NCEs lacking clinical/histological response. Clinical/molecular features and outcomes were retrospectively collected and analysed according to presence/absence of aberrant IELs on FC (cut-off≥20 % CD103+sCD3-CD8-iCD3+ IELs). RESULTS: 52 patients (18 RCD,21 NRCD,13 NCEs; 38F, 55±13 years; median follow-up 30 months, IQR 2-58) underwent 100 FC IELs determinations. 22/52 had ≥2 FC determinations and IEL phenotype remained unchanged over time in all them (κ=1.00). Aberrant IEL phenotype in CD was associated with increased mortality (HR 4.2, 95 % CI 1.5-11.9, p < 0.01). No patients with NCEs had an aberrant IEL phenotype at FC, although 3/13 developed lymphoma and 4/13 died. Concordance of FC was fair with both IHC (κ=0.40) and γ-TCR clonality analysis (κ=0.22). CONCLUSION: FC is accurate for assessing and monitoring IEL phenotype and providing important prognostic information in celiac patients. Further study is needed on its role in NCEs.

Updates in the diagnosis and management of coeliac disease.

Coeliac disease is a common autoimmune disorder induced by ingesting gluten, the protein component of wheat, barley, and rye. It is estimated that one-in-hundred people worldwide have coeliac disease, of whom the majority remain undiagnosed. Coeliac disease is characterized by a wide range of gastrointestinal and extraintestinal symptoms but can also present asymptomatically. Diagnosing coeliac disease depends on the concordance of clinical, serological and histopathological data. However, the diagnosis can be challenging and frequently overlooked. Undiagnosed coeliac disease is associated with an increased risk of complications and detrimental effects on quality of life. Early diagnosis and treatment of coeliac disease are necessary to reduce the risk of long-term complications.

A Combination Therapy in a Rare Case of Adult-Onset Autoimmune Enteropathy.

Autoimmune enteropathy (AIE) is a differential diagnosis of incurable chronic diarrhea, malnutrition, and weight loss. This type of diarrhea is associated with protein enteropathy that usually affects the small intestine. The diagnosis of AIE is based on chronic diarrhea, malabsorption, specific histological result, antibodies against enterocytes, and excluding similar conditions. In this case, a 28-year-old female presented with diarrhea, lower limb edema, weight loss, and electrolyte imbalances. Endoscopic examination demonstrated duodenal villous atrophy, while duodenal biopsies revealed villous blunting, scattered intraepithelial lymphocytes, and crypt hyperplasia in the lamina propria. The patient was treated with immunosuppressive treatment including methylprednisolone and azathioprine, achieving clinical remission.

Olmesartan-Induced Enteropathy: A Case Report.

Patients with olmesartan-induced enteropathy, a rare illness, frequently endure prolonged diarrhea and weight loss with no apparent cause. Because this adverse event's clinical and histological characteristics mimic those of other small intestine illnesses, it can be challenging to recognize it in a timely manner. We report a case of olmesartan-induced enteropathy in a 58-year-old male who had been on olmesartan for several years. Recently, during his travel to Greece, he developed diarrhea lasting several weeks. This was accompanied by a significant weight loss of 35 lbs, acute kidney injury, and hypokalemia. Extensive negative workup, including esophagogastroduodenoscopy (EGD) with normal biopsy of esophagus, stomach, duodenum, and terminal ileum, and colonoscopy with biopsies, autoimmune serologies, and infectious disease workup, led to a diagnosis of olmesartan-induced enteropathy as a diagnosis of exclusion. Diarrhea improved/resolved within a few days after stopping olmesartan in our patient.

Adult-Onset Autoimmune Enteropathy: A Case Report.

Small bowel villous atrophy is most often caused by celiac disease in the Western world, but other diseases should be explored in patients without positive serology. Adult-onset autoimmune enteropathy (AIE) is a rare cause of villous atrophy first known in children with T-cell dysregulation but also seen in adults with autoimmune predispositions. Here, an 82-year-old woman with autoimmune thyroiditis was admitted with weight loss and watery diarrhoea not responding to diet change. Endoscopy revealed villous atrophy both in the duodenum and in the ileum, but no positive celiac serology. A diagnosis of autoimmune enteropathy was made based on chronic diarrhoea not responding to diet change, autoimmune predisposition, villous atrophy, typical histological findings, and no evidence of immunodeficiency or medications causing villous atrophy. The patient was treated to good effect with corticosteroids but needed total parenteral nutrition while admitted. AIE should be considered in villous atrophy without positive celiac serology.

Celiac disease and risk of microscopic colitis: A nationwide population-based matched cohort study.

BACKGROUND: An association has been reported between celiac disease (CD) and microscopic colitis (MC). However, large, population-based cohort studies are rare. OBJECTIVE: To systematically examine the association between CD and MC in a large, nationwide cohort. METHODS: We conducted a nationwide population-based matched cohort study in Sweden of 45,138 patients with biopsy-verified CD (diagnosed in 1990-2016), 223,149 reference individuals, and 51,449 siblings of CD patients. Data on CD and MC were obtained from all (n = 28) pathology departments in Sweden. Adjusted hazard ratios (aHRs) were calculated using Cox regression. RESULTS: During follow-up, 452 CD patients and 197 reference individuals received an MC diagnosis (86.1 vs. 7.5 per 100,000 person-years). This difference corresponded to an aHR of 11.6 (95% confidence interval [CI] = 9.8-13.8) or eight extra MC cases in 1000 CD patients followed up for 10 years. Although the risk of MC was highest during the first year of follow-up (aHR 35.2; 95% CI = 20.1-61.6), it remained elevated even after 10 years (aHR 8.1; 95% CI = 6.0-10.9). Examining MC subtypes lymphocytic colitis (LC) and collagenous colitis (CC) separately, the aHR was 12.4 (95% CI = 10.0-15.3) for LC and 10.2 (95% CI = 7.7-13.6) for CC. MC was also more common before CD (adjusted odds ratio [aOR] = 52.7; 95% CI = 31.4-88.4). Compared to siblings, risk estimates decreased but remained elevated (CD and later MC: HR = 6.2; CD and earlier MC: aOR = 7.9). CONCLUSION: Our study demonstrated a very strong association of MC with CD with an increased risk of future and previous MC in CD patients. The magnitude of the associations underscores the need to consider the concomitance of these diagnoses in cases in which gastrointestinal symptoms persist or recur despite a gluten-free diet or conventional MC treatment. The comparatively lower risk estimates in sibling comparisons suggest that shared genetic and early environmental factors may contribute to the association between CD and MC.

Interferon-Driven Immune Dysregulation in Common Variable Immunodeficiency-Associated Villous Atrophy and Norovirus Infection.

PURPOSE: About 15% of patients with common variable immunodeficiency (CVID) develop a small intestinal enteropathy, which resembles celiac disease with regard to histopathology but evolves from a distinct, poorly defined pathogenesis that has been linked in some cases to chronic norovirus (NV) infection. Interferon-driven inflammation is a prominent feature of CVID enteropathy, but it remains unknown how NV infection may contribute. METHODS: Duodenal biopsies of CVID patients, stratified according to the presence of villous atrophy (VA), IgA plasma cells (PCs), and chronic NV infection, were investigated by flow cytometry, multi-epitope-ligand cartography, bulk RNA-sequencing, and RT-qPCR of genes of interest. RESULTS: VA development was connected to the lack of intestinal (IgA+) PC, a T helper 1/T helper 17 cell imbalance, and increased recruitment of granzyme+CD8+ T cells and pro-inflammatory macrophages to the affected site. A mixed interferon type I/III and II signature occurred already in the absence of histopathological changes and increased with the severity of the disease and in the absence of (IgA+) PCs. Chronic NV infection exacerbated this signature when compared to stage-matched NV-negative samples. CONCLUSIONS: Our study suggests that increased IFN signaling and T-cell cytotoxicity are present already in mild and are aggravated in severe stages (VA) of CVID enteropathy. NV infection preempts local high IFN-driven inflammation, usually only seen in VA, at milder disease stages. Thus, revealing the impact of different drivers of the pathological mixed IFN type I/III and II signature may allow for more targeted treatment strategies in CVID enteropathy and supports the goal of viral elimination.

Clinical and demographic comparison of celiac disease diagnosed during adulthood versus childhood and adolescence: A single-center experience.

Background and Aim: Celiac disease (CeD) is mainly reported from the northern and western parts of India. In central India, it is believed to be a disease of children, with limited data among adults diagnosed for the first time after the age of 18 years. Hence, we aimed to describe CeD's clinical and demographic features among adults and children/adolescents in central India. Methods: This is a retrospective analysis of a prospectively maintained database of all patients diagnosed for CeD from 2010 to 2019. The disease in adults was confirmed when symptoms developed for the first time after 18 years and had positive anti-transglutaminase antibodies with villous atrophy on duodenal biopsy. It was compared with pediatric patients with CeD diagnosed during the same time period. Results: Of the 170 patients diagnosed with CeD, 118 were adults and 52 were children or adolescents. The mean age of presentation of adult CeD was 37.3 ± 11.93 years, while in the pediatric and adolescent group it was 9.19 ± 5.4 years. Classical presentation with chronic, painless, small-bowel-type diarrhea was seen in 44.1% of adults compared to 57.7% in the pediatric age group. Among the adult patients, 55.9% presented with nonclassical symptoms, which included abdominal pain (40.7%) and weight loss (36.4%). The common presenting symptom in children other than diarrhea was weight loss (50%) and abdominal pain (34.6%). Conclusion: CeD is common in central India, with an increasing number of patients being diagnosed for the first time after 18 years of age and presenting more often with nonclassical symptoms.

Small bowel villous atrophy due to immune-checkpoint inhibitors: report of two cases and literature review.

The differential diagnosis of non-coeliac enteropathies (NCEs) is challenging and includes a wide range of aetiologies. Drug-induced NCEs are relatively common and characterized by duodenal villous atrophy, which resolves upon suspension of the offending drug. Immune-checkpoint inhibitors (ICIs), targeting molecules involved in the activation of cytotoxic T cells by targeting, for example, PD-1, PD-L1 and CTLA4, are increasingly used for many types of cancers. Adverse events occurring in the gastrointestinal tract have been described, predominantly in the form of immune-mediated colitis mimicking inflammatory bowel disease. Small bowel involvement whilst on ICI therapy is also possible, though less well described. Herein, we describe two cases of enteropathy with villous atrophy and negative coeliac serology due to ICIs: a 65-year-old man affected by stage IV pulmonary adenocarcinoma under treatment with pembrolizumab and an 18-year-old woman affected by stage IV auricular melanoma who was treated with nivolumab. We also provide a review of the current literature describing small bowel involvement during therapy with ICIs, alone or in combination, for different types of solid tumours. Implications for clinical practice include considering the possibility of small bowel involvement in oncological patients treated with ICIs and the inclusion of ICIs amongst the iatrogenic causes of NCE with villous atrophy. Enteropathies due to ICIs may also represent a pathogenetic model for the understanding of the molecular mechanisms leading to villous atrophy in NCE.

Seronegative Celiac Disease - A Challenging Case.

Celiac disease is an inflammatory disorder of the small intestine caused by sensitivity to gluten. This enteropathy results from the interaction between genetics, autoimmunity, and an environmental trigger (gluten). It can manifest at all ages. We present a case of a 76-year-old woman with nausea and vomiting for six months. She reported asthenia, weight loss, and a brief period of diarrhea without blood or mucus. The search for evidence of infection, tumours, and endocrinopathies was negative, as well as the immunological study, including antibodies for celiac disease. Upper endoscopy with biopsies revealed villous atrophy. Capsule endoscopy showed macroscopic features suggestive of celiac/Whipple's disease. Duodenal biopsies were reviewed, and Whipple's disease was considered unlikely. The genetic analysis was positive for HLA DR7-DQ2. After one year on a gluten-free diet, there was a clinical and histological improvement. The diagnosis of seronegative celiac disease is complex and requires the exclusion of other causes of villous atrophy, as well as a histological improvement after one year of treatment. The genetic test has a high negative predictive value.

A Mouse Model of Celiac Disease.

The design and use of mouse models that reproduce key features of human diseases are critical to advance our understanding of the pathogenesis of autoimmune diseases and to test new therapeutic strategies. Celiac disease is a unique organ-specific autoimmune-like disorder occurring in genetically susceptible individuals carrying HLA-DQ2 or HLA-DQ8 molecules who consume gluten. The key histological characteristic of the disease in humans is the destruction of the lining of the small intestine, a feature that has been difficult to reproduce in immunocompetent animal models. This unit describes the DQ8-Dd -villin-IL-15 transgenic mouse model of CeD, which was engineered based on the knowledge acquired from studying CeD patients' intestinal samples, and which represents the first animal model that develops villous atrophy in an HLA- and gluten-dependent manner without administration of any adjuvant. We provide detailed protocols for inducing and monitoring intestinal tissue damage, evaluating the cytotoxic properties of intraepithelial lymphocytes that mediate enterocyte lysis, and assessing the activation of the enzyme transglutaminase 2, which contributes to the generation of highly immunogenic gluten peptides. Detailed protocols to prepare pepsin-trypsin digested gliadin (PT-gliadin) or chymotrypsin-digested gliadin (CT-gliadin), which allow antibody detection against native or deamidated gluten peptides, are also provided in this unit. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Induction of celiac-like disease in DQ8-Dd -villin-IL-15tg mice Basic Protocol 2: Histological assessment of villous atrophy Support Protocol 1: Morphometric assessment of villous/crypt ratio Support Protocol 2: Evaluation of epithelial cells renewal Support Protocol 3: Evaluation of the density of intraepithelial lymphocytes Basic Protocol 3: Analysis of cytotoxic intraepithelial lymphocytes Basic Protocol 4: Transglutaminase 2 activation and measurement of antibodies against native and deamidated gluten peptides Support Protocol 4: Preparation of CT-gliadin Support Protocol 5: Preparation of PT-gliadin.

A No-Biopsy Approach for the Diagnosis of Celiac Disease in Adults: Can It Be Real?

Background and objective Pediatric guidelines on the diagnosis of celiac disease (CD) have reported that the positivity of anti-endomysium antibodies in the presence of anti-transglutaminase antibodies (TGA) 10 times higher than normal is sufficient for the diagnosis. In this study, we aimed to evaluate whether this diagnostic process for children can also be applied to adult patients. Materials and methods We retrospectively examined patients aged >18 years who were diagnosed with CD. The results of serological tests and endoscopic biopsy were evaluated. Patients with more than one month of duration between celiac serology and endoscopy, those diagnosed with CD before admission, those on a gluten-free diet, and those with selective IgA deficiency were excluded from the study. Results A total of 269 patients were included in the study. TGA value was significantly higher in patients with villous atrophy (p<0.001) and positively correlated with mucosal damage (r=0.60, p<0.01). Considering the cut-off value of 100 U/mL (>10 ULN) for the TGA antibodies, in line with the criteria regulated by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) for the diagnosis of CD, the sensitivity was 71.64%, the specificity was 100%, and the positive predictive value (PPV) was 100%. When the cut-off value was taken as 29.42 U/mL, the sensitivity was 100% and the specificity was 99.5%. For a TGA cut-off value of 52.7 U/mL (5.27 ULN), which determines the presence of partial or complete villous atrophy in the evaluation made considering mucosal damage, the sensitivity was 90%, the specificity was 100%, and the PPV was 100%. Conclusion Based on our findings, TGA titers were highly effective in demonstrating CD-related mucosal damage. This study endorses a biopsy-free strategy in adult patients in line with the ESPGHAN criteria. Local validation of test-specific thresholds will ensure that this approach has a significant impact on adult patients.

Small intestinal resident eosinophils maintain gut homeostasis following microbial colonization.

The intestine harbors a large population of resident eosinophils, yet the function of intestinal eosinophils has not been explored. Flow cytometry and whole-mount imaging identified eosinophils residing in the lamina propria along the length of the intestine prior to postnatal microbial colonization. Microscopy, transcriptomic analysis, and mass spectrometry of intestinal tissue revealed villus blunting, altered extracellular matrix, decreased epithelial cell turnover, increased gastrointestinal motility, and decreased lipid absorption in eosinophil-deficient mice. Mechanistically, intestinal epithelial cells released IL-33 in a microbiota-dependent manner, which led to eosinophil activation. The colonization of germ-free mice demonstrated that eosinophil activation in response to microbes regulated villous size alterations, macrophage maturation, epithelial barrier integrity, and intestinal transit. Collectively, our findings demonstrate a critical role for eosinophils in facilitating the mutualistic interactions between the host and microbiota and provide a rationale for the functional significance of their early life recruitment in the small intestine.

Case Report: Tropical sprue, diagnostic challenges of an old but unrecognized disease.

Tropical sprue (TS) is a post-infective disease of the small bowel characterized by a malabsorption syndrome affecting tropics inhabitants and visitors. Diagnosis of TS remains challenging since it can be confused with common diarrheal diseases, especially in non-endemic areas. We report a Tunisian case of latent TS. A 58-year-old male with a history of chronic watery diarrhea, was admitted to the intensive care unit for confusion which was related to a severe metabolic acidosis. Despite the neurological improvement after hydro-electrolytic resuscitation and acid-base disorders correction, the patient continued to have three to five loose stools daily. A nutritional assessment showed a malabsorption syndrome: iron, Vitamin B12and folate deficiencies; normochromic normocytic anemia and hypoalbuminemia. Gastrointestinal endoscopy showed duodenal villous atrophy and biopsy confirmed subtotal villous atrophy with increased intraepithelial lymphocytosis and a thickened hyalonalized sub-epithelial basal lamina. Celiac disease was evoked, however the patient did not improve on a gluten-free diet and the celiac serology was negative. On re-interviewing, we discovered that the patient had spent two months in India three years prior. Given the travel history, clinico-biological and histological data TS was highly considered and a good response to a five-month antibiotic course combined to nutritional supplementation supported this diagnosis. Clinico-biological, endoscopic and histological findings were overlapping between TS and other malabsorption diseases, explaining diagnosis difficulties. TS should be systematically discussed in tropics visitors presenting with chronic diarrhea. Improvement after micronutrient and vitamin deficiencies replacement combined to a prolonged antibiotic course supports the diagnosis of TS.