Autoimmune enteropathy in children and adults

Comprehensive insights into pathogenesis, diagnosis, treatment, and prognosis in adult autoimmune enteropathy

Autoimmune enteropathy (AIE) constitutes a diverse array of disorders characterized by immune dysregulation and gastrointestinal manifestations, chiefly chronic diarrhea. Due to the small number of reported cohorts, the current knowledge and understanding of adult-onset AIE is rare compared with pediatric or syndromic AIE. Pathogenesis might involve genetic predisposition, aberrant immune homeostasis, comorbidities of autoimmune diseases and environmental trigger. Diagnosis relies on a comprehensive assessment encompassing clinical evaluation, laboratory tests, endoscopic findings and histopathological features, yet distinguishing AIE from other disorders with similar presentations poses diagnostic challenges. Treatment strategies predominantly center on immunosuppressive therapies, exhibiting varied efficacy among individuals. Supportive treatment and prevention and management of complications are also important for prognosis. The prospectives of future researches need to explore the genetic and immunological mechanism, the diagnostic modalities and the treatment strategies to improve patient outcomes.

Paediatric Congenital Enteropathies: Clinical and Histological Review

Paediatric congenital enteropathies (PCEs) are a group of rare inherited diseases with a typical early onset in life. Prompt identification and treatment are crucial to avoid potentially fatal consequences. This review aims to provide a paradigmatic framework for clinical and histological identification of PCEs, with an emphasis on congenital conditions involving epithelial shape, trafficking and polarity, enteroendocrine function, immunomodulatory diseases, and extremely early onset inflammatory bowel illness. A proper classification is founded on histopathological characteristics and clinical parameters (such as consanguinity, anomalies in amniotic fluid, prenatal expression or early neonatal onset, stool appearance, persistence of symptoms despite fasting, and extra-intestinal manifestations, etc.). The increasing accessibility and convenience of genetic tests has also accelerated the identification of genes related to specific phenotypes of PCEs, improving the diagnostic and care pathway. As a "niche" pathology, PCEs are susceptible to misdiagnosis due to a limited awareness of these entities, and their identification requires extensive training and specialized facilities. The aim of our review is to emphasize the importance of an integrated approach, combining clinical, histological, and molecular analysis, to achieve a definitive diagnosis and guide the treatment.

Intractable diarrhea in an infant-autoimmune enteropathy: A case report

Autoimmune enteropathy is a rare cause of chronic intractable diarrhea and is present in <1 in 100,000 infants. We report the case of a 9-month-old boy who presented with intractable diarrhea and vomiting. Genetic panel testing revealed a STAT3 heterozygous mutation in exon 6, suggesting infantile-onset multisystem autoimmune disease-1. The patient was initially treated with steroids and sulfasalazine. However, on tapering steroids, he had another episode of diarrhea and was subsequently put on baricitinib to which he responded.

Clinical characteristics and management of autoimmune enteropathy in children: case reports and literature review

BACKGROUND

Autoimmune enteropathy (AIE) defined by intractable diarrhoea and nonceliac enteropathy with villous atrophy, is a rare digestive disease. Case reports of this disease are sporadic and the clinical characteristics of AIE is seldom discussed.

PURPOSE

We evaluate the clinical, laboratory, histopathological features, response to therapy and outcome of AIE in children.

METHOD

We conducted a retrospective analysis of five children with AIE in our hospital. A comprehensive search of MEDLINE was performed using PubMed, through keywords of "autoimmune enteropathy, pediatric or children". The clinical manifestations, endoscopic results, pathological results, and medication therapy of these children were collected and the cases were divided into two groups, infants (≤ 1 year old) and children (> 1 year old).

RESULTS

Five cases treated in our department: one case took eight years to make the final diagnosis; one case was positive for anti-intestinal epithelial cell (AE) antibody; three cases showed crypt apoptosis in histopathology; and two cases showed celiac-like changes. All cases were responsive to glucocorticoid therapy in the early stage of treatment, while three cases required immunosuppressant maintenance. After reviewing the literature, we performed a statistical analysis of 50 cases with a male-to-female ratio of 31:19. Among them, 35 patients (70%) were within 1 year of age, and their clinical manifestations were mainly watery stool (43 cases, 86%), weight loss (28 cases, 56%), abdominal distension (3 cases, 6%), serum AE or anti-goblet cell (AG) antibody positivity (32 cases, 64%), other immune-related antibodies (21 cases, 42%), gene mutations (9 cases, 18%), and family history (21 cases, 42%). All the children showed different degrees of intestinal villous atrophy. Thirty-seven (74%) of the children were treated early, and their clinical symptoms were relieved. Comparing the cases between different age groups, it was found that the mortality rate of children with onset in infancy was higher (P < 0.05), and there was no difference in other autoimmune diseases, AE antibody positivity rates, and other antibodies between the two groups. In addition to survival rate between different age group (P = 0. 005), there was no difference in sex, autoantibody positivity rate, single gene mutation, or family history between the two groups (P > 0.05) through analysis of mortality and clinical remission cases.

CONCLUSION

Endoscopic examination and mucosal pathological examination should be performed to diagnose AIE in children with watery stool and weight loss who fail to be treated with diet therapy. Immunotherapy is the core of medical management of AIE and can improve prognosis. Children with a poor prognosis in infancy should be actively treated to reduce mortality rates associated with AIE.

Autoimmune enteropathy complicated with primary biliary cholangitis

Autoimmune enteropathy is a rare intestinal disease. Here we report an elderly female with autoimmune enteropathy and primary biliary cholangitis who presented with chronic diarrhea, malnutrition and severe hypokalemia and metabolic acidosis. Enteroscopy showed atrophied small intestinal villi with scallop-like and fissure-like changes. Hormone treatment relieved diarrhea. Four months later, she developed primary biliary cholangitis, and the liver function returned to normal after treatment with ursodeoxycholic acid, corticosteroids and immunosuppressants.

Autoimmune liver disease in gastrointestinal conditions

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Enteric Glial Cells in Immunological Disorders of the Gut

Enteric glial cells (EGCs) are one of the major cell types of neural crest lineage distributed in the gastrointestinal tract. EGCs represent an integral part of the enteric nervous system (ENS) and significantly outnumber ENS neurons. Studies have suggested that EGCs would exert essential roles in supporting the survival and functions of the ENS neurons. Notably, recent evidence has begun to reveal that EGCs could possess multiple immune functions and thereby may participate in the immune homeostasis of the gut. In this review article, we will summarize the current evidence supporting the potential involvement of EGCs in several important immunological disorders, including inflammatory bowel disease, celiac disease, and autoimmune enteropathy. Further, we highlight critical questions on the immunological aspects of EGCs that warrant future research attention.

ECCO Topical Review on Clinicopathological Spectrum and Differential Diagnosis of Inflammatory Bowel Disease

INTRODUCTION

Many diseases can imitate inflammatory bowel disease [IBD] clinically and pathologically. This review outlines the differential diagnosis of IBD and discusses morphological pointers and ancillary techniques that assist with the distinction between IBD and its mimics.

METHODS

European Crohn's and Colitis Organisation [ECCO] Topical Reviews are the result of an expert consensus. For this review, ECCO announced an open call to its members and formed three working groups [WGs] to study clinical aspects, pathological considerations, and the value of ancillary techniques. All WGs performed a systematic literature search.

RESULTS

Each WG produced a draft text and drew up provisional Current Practice Position [CPP] statements that highlighted the most important conclusions. Discussions and a preliminary voting round took place, with subsequent revision of CPP statements and text and a further meeting to agree on final statements.

CONCLUSIONS

Clinicians and pathologists encounter a wide variety of mimics of IBD, including infection, drug-induced disease, vascular disorders, diverticular disease, diversion proctocolitis, radiation damage, and immune disorders. Reliable distinction requires a multidisciplinary approach.

Pediatric autoimmune disorders with gastrointestinal expressions: from bench to bedside

The gastrointestinal (GI) tract may be involved in systemic autoimmune diseases or may be the target of organ-specific autoimmunity. Autoimmune enteropathy (AIE) is a rare disorder characterized by severe and protracted diarrhea, weight loss from malabsorption and immune-mediated damage to the intestinal mucosa, generally occurring in infants and young children, only rarely in adult. The salient histopathologic features of AIE are most prominent in the small intestine: villous blunting, crypt hyperplasia, mononuclear cell inflammatory expansion of the lamina propria with intraepithelial lymphocytosis, crypt apoptosis and absence of Paneth cells, goblet cells or both. Esophagus, stomach and colon are frequently also involved. Anti-enterocyte antibodies are identified in the majority of cases, and their presence, even if variable, can help confirming the diagnosis.

The purpose of this review is to provide an overview of the latest immunological advances in AIE, as well as to offer a practical approach for histological diagnosis for 'general' pathologist.

Autoimmune Diseases of Digestive Organs-A Multidisciplinary Challenge: A Focus on Hepatopancreatobiliary Manifestation

It is well known that some pathological conditions, especially of autoimmune etiology, are associated with the HLA (human leukocyte antigen) phenotype. Among these diseases, we include celiac disease, inflammatory bowel disease, autoimmune enteropathy, autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cholangitis. Immunoglobulin G4-related diseases (IgG4-related diseases) constitute a second group of autoimmune gastrointestinal, hepatobiliary and pancreatic illnesses. IgG4-related diseases are systemic and rare autoimmune illnesses. They often are connected with chronic inflammation and fibrotic reaction that can occur in any organ of the body. The most typical feature of these diseases is a mononuclear infiltrate with IgG4-positive plasma cells and self-sustaining inflammatory response. In this review, we focus especially upon the hepatopancreatobiliary system, autoimmune pancreatitis and IgG4-related sclerosing cholangitis. The cooperation of the gastroenterologist, radiologist, surgeon and histopathologist is crucial for establishing correct diagnoses and appropriate treatment, especially in IgG4 hepatopancreatobiliary diseases.

Adult-Onset Autoimmune Enteropathy in an European Tertiary Referral Center

INTRODUCTION

Adult-onset autoimmune enteropathy (AIE) is a rare cause of severe chronic diarrhea because of small intestinal villous atrophy. We report on patients with adult-onset AIE in an European referral center.

METHODS

Retrospective study including patients diagnosed with AIE in the Amsterdam UMC, location VUmc, between January 2003 and December 2019. Clinical, serological, and histological features and response to treatment were reported. The specificity of antienterocyte antibodies (AEA) was evaluated by examining the prevalence of AEA in (i) controls (n = 30) and in patients with (ii) AIE (n = 13), (iii) celiac disease (CD, n = 52), (iv) refractory celiac disease type 2 (n = 18), and (v) enteropathy-associated T-cell lymphoma (EATL, n = 10).

RESULTS

Thirteen AIE patients were included, 8 women (62%), median age of 52 years (range 23-73), and 6 (46%) with an autoimmune disease. AEA were observed in 11 cases (85%), but were also found in CD (7.7%), refractory celiac disease type 2 (16.7%), and EATL (20%). Ten patients (77%) were human leukocyte antigen DQ2.5 heterozygous. Total parenteral nutrition was required in 8 cases (62%). Steroids induced clinical remission in 8 cases (62%). Step-up therapy with rituximab, cyclosporine, infliximab, and cladribine in steroid-refractory patients was only moderately effective. Four patients died (31%), but 4 (31%) others are in long-term drug-free remission after receiving immunosuppressive treatment, including 1 patient who underwent autologous stem cell transplantation.

DISCUSSION

Adult-onset AIE is a rare but severe enteropathy that occurs in patients susceptible for autoimmune disease. Four patients (31%) died secondary to therapy-refractory malabsorption, while immunosuppressive therapy leads to a long-lasting drug-free remission in one-third of patients.

Histopathology of non-IBD colitis practical recommendations from pathologists of IG-IBD Group

Pathologists are often called upon to diagnose colitides that differ from the two main forms of inflammatory bowel disease (IBD). These non-IBD colitides include infectious colitis, microscopic colitis, ischemic colitis, eosinophilic colitis, autoimmune enterocolitis, segmental colitis associated with diverticulosis, drug-induced colitis, radiation colitis and diversion colitis. The diagnosis of these different disease entities relies on the histopathological examination of endoscopic biopsies of the gastrointestinal tract. This paper reviews the main histomorphological characteristics of the various Non-IBD colitides.

Adult autoimmune enteropathy in autoimmune hepatitis patient. Case report and literature review

Autoimmune enteropathy (AIE) is a rare disease characterized by prolonged diarrhea, vomiting and weight loss; although it is mainly a rare pediatric disease, over the years a number of adults have also been found to be affected. In this study, we present a case report of a 73-year-old woman with a history of autoimmune hepatitis, antinuclear (ANA) and positive anti-enterocyte antibodies (AEA), who has suffered two months of intractable diarrhea, nausea, anorexia and severe weight loss. The histological examination of the endoscopic duodenal mucosa biopsies revealed severe shortening and flattening of the villi, resulting in mucosal atrophy. The immunohistochemical study revealed a polymorphic lymphoid population, exhibiting a B cell (CD20+) phenotype in follicles and a T cell phenotype (CD3+) in the diffuse component within the lamina propria. Our patient had a complete recovery after two weeks of taking prednisone and following a gluten-rich diet. To our knowledge this is the first case of autoimmune enteropathy in adults with ANA and AEA 7 years after a diagnosis of autoimmune hepatitis. To date, the patient is still in clinical remission on a low dose of orally administered predinisone without any additional immunosuppression.

Immune-mediated enteropathies: From bench to bedside

Immune-mediated enteropathies are caused by excessive reactions of the intestinal immune system towards non-pathogenic molecules. Enteropathy leads to malabsorption-related symptoms and include (severe) chronic diarrhea, weight loss and vitamin deficiencies. Parenteral feeding and immunosuppressive therapy are needed in severe cases. Celiac disease has long been recognized as the most common immune-mediated enteropathy in adults, but the spectrum of immune-mediated enteropathies has been expanding. Histological and clinical features are sometimes shared among these enteropathies, and therefore it may be challenging to differentiate between them. Here, we provide an overview of immune-mediated enteropathies focused on clinical presentation, establishing diagnosis, immunopathogenesis, and treatment options.

Histopathology of Non-IBD Colitis. A practical approach from the Italian Group for the study of the gastrointestinal tract (GIPAD)

Non-IBD colitides (NIBDC) are intestinal diseases clinically and endoscopically overlapping with Inflammatory Bowel Diseases (IBD), sometimes with a similar histological picture. NIBDC include entities such as infectious colitis, ischemic colitis, pseudomembranous colitis, eosinophilic colitis, autoimmune enterocolitis, segmental colitis associated with diverticulosis, drug-induced colitis, radiation-induced colitis, diversion colitis, and microscopic colitis, this last including two entities: collagenous and lymphocytic colitis. The knowledge of the most useful histological features and the main clinical data for each entity is mandatory in daily clinical practice, for correct pathological diagnosis and clinical management.

Successful Treatment of Refractory Autoimmune Enteropathy With Ustekinumab

Autoimmune enteropathy (AIE) is a rare autoimmune disorder that has been described both in pediatric and adult patients and usually causes intractable watery diarrhea. The management of AIE is not standardized because the disease shows variable response to different immunosuppressive regimens including corticosteroids, azathioprine, cyclophosphamide, 6-mercaptopurine, tacrolimus, cyclosporine-A, infliximab, vedolizumab, and abatacept. We present a patient with adult-onset AIE and intractable high-volume diarrhea resulting in numerous hospitalizations and temporary parenteral nutrition, who is now successfully maintained on ustekinumab. Therefore, ustekinumab should be considered for further evaluation as a therapeutic option in cases of refractory AIE.

A Review of Autoimmune Enteropathy and Its Associated Syndromes

Autoimmune enteropathy is an extremely rare condition characterized by an abnormal intestinal immune response which typically manifests within the first 6 months of life as severe, intractable diarrhea that does not respond to dietary modification. Affected individuals frequently present with other signs of autoimmunity. The diagnosis is made based on a characteristic combination of clinical symptoms, laboratory studies, and histological features on small bowel biopsy. Autoimmune enteropathy is associated with a number of other conditions and syndromes, most notably immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome and autoimmune polyglandular syndrome type 1 (APS-1). Diagnosis and treatment is challenging, and further research is needed to better understand the pathogenesis, disease progression, and long-term outcomes of these conditions.

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.

[Autoimmune enteropathy in adults : A rare and difficult but relevant differential diagnosis of chronic diarrhea]

Autoimmune enteropathy (AIE) was originally believed to be a pediatric disease until there were increasing numbers of adult cases reported over the last 20 years. AIE is an autoimmune disease that manifests as severe chronic diarrhea.The histological hallmark is villous atrophy. Histology alone is not sufficiently sensitive and consistent. Four different histological patterns are known. There are many differential diagnoses to be considered relating to both histology and symptoms.We present the case of a young woman with fatal AIE and homozygous germline-mutation of the CLEC7A gene. The course of disease is documented in multiple intestinal biopsies, which show a morphological change over time.Histology and symptoms often resemble celiac disease. In order to recognize this rare disease early in its course there is a need for a special awareness among attending physicians and pathologists.

Clinical manifestations and gastrointestinal pathology in 40 patients with autoimmune enteropathy

Autoimmune enteropathy (AIE) is a rare condition that may affect pediatric and adult patients, frequently associated with primary immunodeficiencies. We performed a retrospective study on clinical and histological findings from 40 AIE patients. Histological presentation showed a prevalent celiac disease pattern (50%), followed by the mixed pattern (35%), independently of age, chronic active duodenitis (10%), and GVHD-like pattern (5%). Patients with primary immunodeficiencies (24/40) presented mainly with the celiac disease pattern (72.2% versus 22.2%; p < .0001), while patients without primary immunodeficiencies presented with a mixed histological pattern (61.1% versus 13.6%; p < .0001). Our study shows that the prevalent histological presentation is the celiac disease-like pattern, independently of age, and, for the first time, that the histological presentation of AIE differs significantly between patients with and without primary immunodeficiencies. These findings may be helpful for more precise and timely diagnosis and management of this rare disorder.

Biopsy Diagnosis of Celiac Disease: The Pathologist's Perspective in Light of Recent Advances

Celiac disease is a common immune-mediated disorder that occurs in individuals with permissive genetics (HLA-DQ2/DQ8 genotype) following exposure to certain wheat proteins. The histopathologic manifestations of small intestinal mucosal injury (villus atrophy, crypt hyperplasia, and intraepithelial lymphocytosis) are well recognized. However, these findings are not specific for celiac disease, because they are observed in other small intestinal disorders. These mimics include common and rare entities, the list of which continues to grow. This article discusses the histopathology and differential diagnosis of celiac disease and provides the pathologist's perspective on biopsy adequacy, evaluation, and reporting in light of current knowledge.

Autoimmune Enteropathy: An Updated Review with Special Focus on Stem Cell Transplant Therapy

Autoimmune enteropathy (AIE) is a complex disease affecting both children and adults. Although associated with significant morbidity and mortality, the pathophysiology of the disease and its treatment have not been well characterized. This study aims to review the medical literature available on this rare but clinically significant ailment, to help establish a better understanding of its pathophysiology and enumerate the available diagnostic and treatment modalities. A literature search was conducted on PubMed using key terms related to autoimmune enteropathy and intractable diarrhea, with no restrictions on the date of publication or language. We found a total of 98 reports of AIE published in the form of case reports and case series. The evidence reviewed suggests that AIE is a multifaceted disorder that requires a high index of suspicion in the appropriate clinical setting to be able to make an early diagnosis. Current evidence supports the use of supportive care to correct nutritional and metabolic deficiencies, and immunosuppressives and immunomodulators as directed therapies. Hematopoietic stem cell transplant is an aggressive, but successful curative modality for patients with AIE as part of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Cumulative clinical experience with management of AIE has allowed improved outcomes in transplanted and non-transplanted AIE patients even though morbidity and mortality with are still high in patients with this condition. More research is needed to further define the role of new therapies for AIE, and a central registry with participation of multiple institutions might help share and standardize care of patients with this rare but serious condition.

Features of Adult Autoimmune Enteropathy Compared With Refractory Celiac Disease

BACKGROUND & AIMS

Little is known about the features of immune-mediated non-celiac villous atrophies, such as autoimmune enteropathy (AIE). We investigated the demographic, clinical, and histologic features of adults with AIE compared to adults with refractory celiac disease type 1. We also report outcomes of treatment with open-label budesonide.

METHODS

We performed a retrospective case-control of patients with AIE (n = 30) seen at the Mayo Clinic (in Rochester, Minnesota) from 2000 through 2015. Patients with refractory celiac disease type 1 who were treated with open-label budesonide served as controls (n = 42). Biopsy specimens were reviewed for all patients. We collected demographic, clinical, biochemical and histologic data from patients. We also collected data on responses to open-capsule budesonide from patients with AIE (available from 22 patients) and controls (available from 42 patients); the median duration of follow up was 28 months (range, 0-1421 months).

RESULTS

Patients with AIE had a higher proportion of men (60%) and were younger (mean, 44 ± 18 years) than patients with refractory celiac disease type 1 (29% men; P = .002 and mean age, 57 ± 16 years; P = .007). A higher proportion of patients with AIE presented with chronic diarrhea (100%) and weight loss (90%) than patients with refractory celiac disease type 1 (71%; P < .001 and 71%; P = .05, respectively). Based on histologic analysis, there was no significant difference in degree of villous atrophy in intestinal tissues from patients with AIE vs controls (P = .68). However, a greater proportion of patients with RCD had increased intraepithelial lymphocytes (>40 per 100 epithelial cells in 100%) compared with patients with AIE (in 50%) (P = .003). Conventional therapy (systemic steroids) had failed in most patients with AIE (a complete clinical response was reported in only 7 patients) before treatment with open-capsule budesonide was initiated. A clinical response to open-capsule budesonide was reported for 85% of patients with AIE (50% complete response, 35% partial response) compared to 92% of controls (68% complete response, 24% partial response).

CONCLUSIONS

In a retrospective study of 30 patients with AIE, followed for a median 28 months, we found this disease to have has distinct demographic, clinical, and histologic characteristics compared to refractory celiac disease type 1. Most patients with AIE (85%) have a clinical response to budesonide, all of whom were unsuccessfully treated with conventional therapies.

Practical Approach to the Flattened Duodenal Biopsy

Celiac disease features duodenal intraepithelial lymphocytosis with or without villous atrophy. Lymphocytosis without villous atrophy will be proven to represent celiac disease in 10% to 20% of cases. The differential diagnosis is broad: Helicobacter pylori gastritis, NSAID injury and bacterial overgrowth are considerations. Lymphocytosis with villous atrophy is very likely to be celiac disease, but there are mimics to consider, including collagenous sprue, tropical sprue, drug injury, and common variable immunodeficiency. Histologic clues to a diagnosis other than celiac disease include paucity of plasma cells, excess of neutrophils, granulomas, and relative paucity of intraepithelial lymphocytes.

Autoimmune enteropathies

Autoimmune enteropathy (AIE) is a rare condition characterized by intractable diarrhea and immune-mediated injury of the intestinal mucosa. As the clinical and histopathologic manifestations of this disease are highly variable, its diagnosis is challenging for both clinicians and pathologists. In fact, the term autoimmune enteropathies is likely more appropriate since the clinicopathologic manifestations are observed in association with a heterogeneous group of disorders. The pathophysiology of AIE has not been fully elucidated. It appears to result from dysregulation of intestinal immunity and particularly in children, often presents in association with immunodeficiency. The overarching histopathologic changes seen in AIE include mucosal inflammation and epithelial injury, although this can manifest in the form of different patterns. Recognition of the clinical settings and of the various histologic patterns can aid the pathologist in establishing the correct diagnosis.

Newcomers in paediatric GI pathology: childhood enteropathies including very early onset monogenic IBD

Childhood enteropathies are a group of diseases causing severe chronic (>2-3 weeks) diarrhoea often starting in the first week of life with the potential for fatal complications for the affected infant. Early identification and accurate classification of childhood enteropathies are, therefore, crucial for making treatment decisions to prevent life-threatening complications. Childhood enteropathies are classified into four groups based on the underlying pathology: (i) conditions related to defective digestion, absorption and transport of nutrients and electrolytes; (ii) disorders related to enterocyte differentiation and polarization; (iii) defects of enteroendocrine cell differentiation; and (iv) disorders associated with defective modulation of intestinal immune response. While the intestinal mucosa is usually normal in enteropathies related to congenital transport or enzyme deficiencies, the intestinal biopsy in other disorders may reveal a wide range of abnormalities varying from normal villous architecture to villous atrophy and/or inflammation, or features specific to the underlying disorder including epithelial abnormalities, lipid vacuolization in the enterocytes, absence of plasma cells, lymphangiectasia, microorganisms, and mucosal eosinophilic or histiocytic infiltration. This review intends to provide an update on small intestinal biopsy findings in childhood enteropathies, the "newcomers", including very early onset monogenic inflammatory bowel disease (IBD), in particular, for the practicing pathologist.

Prolonged tacrolimus for pediatric gastrointestinal disorder: Double-edged sword?

BACKGROUND

Although tacrolimus (TAC) can induce remission in children with refractory inflammatory bowel disease (IBD) or autoimmune gastroenteropathy (AGE), its use in maintenance therapy remains controversial. The aim of this study was to investigate the potential nephrotoxic nature of prolonged TAC use.

METHODS

This retrospective study reviewed children with gastrointestinal disorder who underwent kidney biopsy for the evaluation of renal damage during TAC therapy for >1 year. The clinical and histological features of renal damage were evaluated in this single-institution cohort.

RESULTS

Eighteen of 121 children with IBD and two children with AGE followed at a national children hospital in Tokyo, Japan, received TAC between August 2006 and April 2013. Among them, five (Crohn's disease, n = 3; autoimmune gastropathy, n = 1; autoimmune enteropathy, n = 1) received TAC for >1 year, and underwent kidney biopsy. All five had achieved remission on TAC, but had histological evidence of chronic nephrotoxicity. Renal damage in one patient with relatively low TAC trough level remained mild. Estimated glomerular filtration rate (eGFR) at the time of kidney biopsy was lower than at the initiation of TAC in all four available patients. Among them, eGFR improved in one patient after the decrease or discontinuation of TAC.

CONCLUSIONS

TAC appeared to be effective in children with refractory gastrointestinal disorder, but long-term use seems to cause irreversible renal damage. Rigorous monitoring of eGFR and kidney biopsy in selected cases should be considered for the proper adjustment of TAC.

Approach to the Management of Autoimmunity in Primary Immunodeficiency

Primary immunodeficiency diseases (PIDs) consist of a genetically heterogeneous group of immune disorders that affect distinct elements of the immune system. PID patients are more prone to infections and non-infectious complications, particularly autoimmunity. The concomitance of immunodeficiency and autoimmunity appears to be paradoxical and leads to difficulty in the management of autoimmune complications in PID patients. Therefore, management of autoimmunity in patients with PID requires special considerations because dysregulations and dysfunctions of the immune system along with persistent inflammation impair the process of diagnosis and treatment.

Autoimmune enteropathy and hepatitis in pediatric heart transplant recipient

AIE is a rare disorder in children that presents with severe diarrhea and malabsorption, caused by immune-mediated damage to intestinal mucosa. AIE is often associated with various syndromes of immunodeficiency including IPEX syndrome (immune dysregulation, polyendocrinopathy and enteropathy, X-linked). Dysfunctional T regulatory cells are the source of pathology in both IPEX syndrome and AIE as they are essential in maintaining tolerance to self-antigens and eliminating autoreactive B cells. This case report describes a 10-year-old cardiac transplant and total thymectomy patient on chronic immunosuppression with tacrolimus that presented with AIE and extraintestinal manifestations of cyclical hepatitis. Transition from tacrolimus to sirolimus successfully increased T regulatory cells and resolved enteritis and hepatitis symptoms. Data support that thymectomy at <1 year of age increases risk of autoimmune disease due to abnormal immune maturation. Studies suggest that the sirolimus promotes the upregulation of the FoxP3 protein that is classically associated with Tregs. In turn, Tregs prevent the maturation of autoreactive B cells that lead to autoimmune reactions.

Small bowel villous atrophy: celiac disease and beyond

Small bowel villous atrophy can represent a diagnostic challenge for gastroenterologists and pathologists. In Western countries small bowel atrophy and mild non-atrophic alterations are frequently caused by celiac disease. However, other pathology can mimic celiac disease microscopically, widening the differential diagnosis. The several novelties on this topic and the introduction of the device-assisted enteroscopy in the diagnostic flowchart make an update of the literature necessary. Areas covered: In this review, a description of the different clinical scenarios when facing with small bowel mucosal damage, particularly small bowel atrophy, is described. The published literature on this subject has been summarized and reviewed. Expert commentary: When an intestinal mucosal alteration is histologically demonstrated, the pathology report forms part of a more complex workup including serological data, clinical presentation and clinical history. A multidisciplinary team, including pathologists and enteroscopy-devoted endoscopists, is frequently required to manage patients with small bowel alterations, especially in cases of severe malabsorption syndrome.

Seronegative Adult Autoimmune Enteropathy in a Male Traveler

Autoimmune enteropathy (AIE) is rare but damaging. The lack of consistent objective findings makes diagnosis a challenge. A 45-year-old male developed noninfectious diarrhea with significant weight loss and electrolyte abnormalities. Computed tomography delineated enteritis. Colonoscopy and esophagogastroduodenoscopy showed villous atrophy, chronic inflammation, and ulceration of the terminal ileum and cecum. Pathology showed cryptitis with apoptosis and abscesses throughout the small and large bowel and absent goblet cells. Steroids rapidly improved symptoms. Anti-enterocyte antibody serologies were negative. Management can be challenging, and, in this case, the patient initially improved with budesonide and infliximab but required alternative anti-tumor necrosis factor therapy after relapsing. This is an unusual presentation of seronegative AIE, which should be considered in cases of persistent severe diarrhea.

Autoimmune enteropathy

Autoimmune enteropathy (AIE) is a very rare clinical entity primarily reported in infancy. In recent years, adult involvement has also been documented. Intractable diarrhea is the main manifestation, which is associated with small bowel villous atrophy. Corticosteroids are considered the first-choice therapy for AIE. In some patients, immunosuppressive therapies are necessary.

Successful Hematopoietic Stem Cell Transplantation in a Patient with LPS-Responsive Beige-Like Anchor (LRBA) Gene Mutation

PURPOSE

Autosomal recessive mutations in LRBA, encoding for LPS-responsive beige-like anchor protein, were described in patients with a common variable immunodeficiency (CVID)-like disease characterized by hypogammaglobulinemia, autoimmune cytopenias, and enteropathy. Here, we detail the clinical, immunological, and genetic features of a patient with severe autoimmune manifestations.

METHODS

Whole exome sequencing was performed to establish a molecular diagnosis. Evaluation of lymphocyte subsets was performed for immunological characterization. Medical files were reviewed to collect clinical and immunological data.

RESULTS

A 7-year-old boy, born to consanguineous parents, presented with autoimmune hemolytic anemia, hepatosplenomegaly, autoimmune thyroiditis, and severe autoimmune gastrointestinal manifestations. Immunological investigations revealed low immunoglobulin levels and low numbers of B and NK cells. Treatment included immunoglobulin replacement and immunosuppressive therapy. Seven years after disease onset, the patient developed severe neurological symptoms resembling acute disseminated encephalomyelitis, prompting allogeneic hematopoietic stem cell transplantation (HSCT) with the HLA-identical mother as donor. Whole exome sequencing of the patient uncovered a homozygous 1 bp deletion in LRBA (c.7162delA:p.T2388Pfs*7). Importantly, during 2 years of follow-up post-HSCT, marked clinical improvement and recovery of immune function was observed.

CONCLUSIONS

Our data suggest a beneficial effect of HSCT in patients with LRBA deficiency.

How to Diagnose and Treat IBD Mimics in the Refractory IBD Patient Who Does Not Have IBD

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract and includes both Crohn's disease and ulcerative colitis. Patients with IBD often present with abdominal pain, diarrhea, and rectal bleeding but may also have a wide variety of other symptoms such as weight loss, fever, nausea, vomiting, and possibly obstruction. Given that the presentation of IBD is not specific, the differential diagnosis is broad and encompasses a wide spectrum of diseases, many of which can mimic and/or even coexist with IBD. It is important for physicians to differentiate symptoms due to refractory IBD from symptoms due to IBD mimics when a patient is not responding to standard IBD treatment. Many of the various IBD mimics include infectious etiologies (viral, bacterial, mycobacterial, fungal, protozoal, and helminthic infections), vascular causes, other immune causes including autoimmune etiologies, drug-induced processes, radiation-induced, and other etiologies such as small intestinal bacterial overgrowth, diverticulitis, and bile acid malabsorption. Thoughtful consideration and evaluation of these potential etiologies through patient history and physical examination, as well as appropriate tests, endoscopic evaluation, and cross-sectional imaging is required to evaluate any patient presenting with symptoms consistent with IBD.

The biopsy pathology of non-coeliac enteropathy

Tropical sprue (TS) is a malabsorption syndrome of presumed infectious aetiology that affects residents of (or visitors to) the tropics. The histological changes of TS are similar to those of coeliac disease, with increased intraepithelial lymphocytes being central to both. Unlike in coeliac disease, however, a completely flat small bowel biopsy is uncommon in TS. TS typically involves the terminal ileum, whereas coeliac disease does not. Small intestinal bacterial overgrowth (SIBO) has been defined as an increase in number and/or a change in the type of bacteria in the upper gut. Conditions that predispose to SIBO are largely those that decrease or interfere with small bowel motility. The mucosal histology is variable, and may include modest villous blunting accompanied by increased lamina propria and epithelial inflammation. Autoimmune enteropathy (AE) is a family of rare diseases that share common themes such as immunodeficiency states and autoantibodies. AE cases typically have marked villous atrophy similar to that in fully developed coeliac disease, but they lack the intense surface epithelial lymphocytosis. Apoptosis and lymphocyte infiltration at the base of the crypts, crypt abscesses and cryptitis are also seen. Patients with anti-goblet cell antibodies can have a lack of goblet cells, endocrine cells, and Paneth cells.

Wireless capsule endoscopy as a tool in diagnosing autoimmune enteropathy

Autoimmune enteropathy (AE) is an immune mediated illness of the intestinal mucosa. The cause is unknown, and the diagnosis is based on typical characteristics displayed. There is no gold standard for treatment. We present two adult cases of AE and demonstrate the challenges in establishing the diagnosis. The extensive diagnostic work up excluded other more common causes of protracted diarrhoea. Wireless capsule endoscopy (WCE) displayed universal small intestinal mucosal damage with shortened villi that led to the suspicion of AE in both patients. The diagnosis was confirmed with microscopy, showing shortened villi, villous blunting and hyperplasia of crypts in both patients. In one patient, deep crypt lymphocytosis with minimal intraepithelial lymphocytosis was found as well. Both patients were successfully treated with high-dose immunosuppressant therapy to induce and maintain remission. Use of WCE as a diagnostic tool was invaluable in establishing the diagnosis of AE.

Very early-onset inflammatory bowel disease: gaining insight through focused discovery

The pathogenesis of pediatric inflammatory bowel disease (IBD) is only partially understood. Strong evidence implicates a strong genetic component including high monozygotic twin concordance and familial disease phenotype concordance rates. Genome-wide association studies have identified associations between >160 genetic loci and the risk for developing IBD. The roles of implicated genes are largely immune-mediated, although other functions include cellular migration, oxidative stress, and carbohydrate metabolism. Additionally, growing literature describes monogenic causes of IBD that frequently present as infantile or very early-onset IBD. The interplay between IBD risk single nucleotide polymorphisms and rare genetic variants has yet to be determined. Studying patients with very early-onset IBD may elicit genetic factors that could be applied to broader populations of IBD. This review describes what is known about the genetic causes of very early-onset IBD and genetic strategies that may unravel more of the genetic causes of IBD.

Gastrointestinal immunity against tryptophan hydroxylase-1, aromatic L-amino-acid decarboxylase, AIE-75, villin and Paneth cells in APECED

Gastrointestinal dysfunction is a disabling manifestation of APECED possibly related to an autoimmune intestinal aggression. We evaluated its features in a cohort of 31 Finnish patients. The most frequent manifestations were constipation (48%), diarrhea, dysphagia and retrosternal pain (45%). AADC and TPH-1 autoantibodies were detected in 51% and 45% of the patients, respectively. Forty-three percent displayed a T-cell response to AADC. One third of the patients also had AIE-75 (33%) and villin (29%)-specific autoantibodies while antibodies against brush borders and Paneth cells were detected in 29% and 20%, respectively. Intestinal IL-17 expression was absent/decreased in 77% of the cases. Duodenal CgA and serotonin expression was absent/decreased in 50% and 66% of the patients, respectively. Constipation correlated with lacking serotonin expression and AADC antibodies (p < 0.05).

IPEX syndrome caused by a novel mutation in FOXP3 gene can be cured by bone marrow transplantation from an unrelated donor after myeloablative conditioning

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare primary immunodeficiency caused by inherited defects in the FOXP3 gene that impair regulatory T cells. IPEX syndrome can be cured by hematopoietic stem cell transplantation (HSCT) from HLA-matched unrelated donors (MUD); however, the best conditioning prior to HSCT for IPEX syndrome is not known.

Here we report on a patient suffering from IPEX syndrome, including immune-mediated colitis and membranous nephropathy, without polyendocrinopathy, caused by a novel mutation in the Forkhead domain of the FOXP3 gene. The patient's symptoms resolved following MUD HSCT after myeloablative conditioning performed at 16 months of age. The patient is clinically well, 3 years after HSCT, with robust immune reconstitution and fully engrafted. The lack of extensive autoimmune damage might have contributed to the patient's favourable outcome following MUD HSCT with myeloablative conditioning.

Statement of novelty: We describe a novel mutation in the FOXP3 gene causing IPEX syndrome and the correction of IPEX syndrome with bone marrow transplant from a HLA-matched unrelated donor following myeloablative conditioning.

Gastrointestinal biopsy findings of autoimmune enteropathy: a review of 25 cases

Autoimmune enteropathy (AIE) is a rare disorder characterized by severe diarrhea and small intestinal mucosal atrophy resulting from immune-mediated injury. It remains a challenging diagnosis because of its clinicopathologic variability. To better understand its histopathologic features, we describe the gastrointestinal biopsy findings of 25 patients, including children and adults. The most common finding on small intestinal biopsy (13/25 cases, 52%) was villous blunting, expansion of the lamina propria by mixed but predominantly mononuclear inflammation, and neutrophilic cryptitis with or without crypt microabscesses. In 5 cases (20%), the duodenum exhibited changes indistinguishable from celiac disease, with villous blunting and intraepithelial lymphocytosis. Increased crypt apoptosis with minimal inflammation, resembling acute graft-versus-host disease, was observed in 4 cases (16%). The remaining 3 cases (12%) exhibited a mixture of 2 or more of the above patterns. Mucosal abnormalities outside the small intestine were present in all 24 cases with available biopsies (100%), with the stomach most commonly affected (19/22 cases, 86%), followed by the colon (14/22, 64%) and esophagus (5/18, 28%). Findings in non-small intestinal sites were variable and included mixed active and chronic inflammation, chronic inflammation alone, intraepithelial lymphocytosis, and increased apoptosis resembling acute graft-versus-host disease. In summary, AIE most commonly presents as an active enteritis with villous blunting and expansion of the lamina propria by mixed inflammation. Mucosal abnormalities are frequently seen elsewhere in the gut. AIE may thus be better regarded as a pan-gastrointestinal autoimmune disorder, and biopsies from sites other than the small intestine may greatly facilitate its diagnosis.

Glutamine-supplemented parenteral nutrition and probiotics in four adult autoimmune enteropathy patients

To evaluate the effects of glutamine-supplemented parenteral nutrition (PN) and probiotics in adult autoimmune enteropathy (AIE) patients. Four adult AIE patients were identified from April 2006 to January 2012. Clinical and nutritional data were obtained from the patients' medical records. Glutamine-supplemented PN started immediately when the AIE diagnosis was confirmed. The total PN duration was 351 days. According to the PN prescription, the average caloric intake ranged from 20 to 25 kcal/kg/day, and the protein intake ranged from 1.2 to 1.5 g/kg/day. Alanyl-glutamine (20 g/day) was administered to AIE patients for 4 weeks followed by a 2-week break, and this treatment schedule was repeated when PN lasted for more than 6 weeks. Body weight gain and an increased serum albumin level were achieved after PN, and defecation frequency and quality also improved. Each patient received oral supplements, 250 mL of Ensure and two probiotics capsules (each capsule containing 0.5×108 colonies) three times a day when enteral nutrition started. Three AIE patients were successfully weaned off PN, and one patient died of pneumonia. Glutamine-supplemented PN and probiotics show promise in managing patients with AIE and related malnutrition.

Pediatric autoimmune enteropathy: an entity frequently associated with immunodeficiency disorders

The term pediatric autoimmune enteropathy was originally applied to a form of intractable diarrhea seen in children under the age of 6 months and characterized by male predominance, concurrent autoimmune-associated disorders, circulating gut autoantibodies, a lack of severe immunodeficiency and small bowel atrophy with prominent crypt apoptosis. However, recent studies have cast doubt over the specific clinicopathologic findings associated with this entity. We, therefore, collected 178 gastrointestinal biopsies from 14 patients and examined their clinical, serologic and pathologic findings. Patients at presentation ranged in age from birth to 15.9 years (median, 5.5 months; mean, 4.1 years) and included six males and eight females. All children suffered from chronic watery diarrhea and malnutrition. Concomitant-associated disorders were noted in 11 (79%) cases and included 10 (71%) with an immunodeficiency disorder and/or another autoimmune-related disease. Eleven patients (79%) were positive for anti-enterocyte antibodies. The salient findings of autoimmune enteropathy were most prominent in the small intestines and the majority (79%) of patients demonstrated villous blunting, crypt hyperplasia, mononuclear cell inflammatory expansion of the lamina propria and crypt apoptosis. The remaining (21%) patients showed marked intraepithelial lymphocytosis reminiscent of celiac disease. Further, acute cryptitis and crypt abscesses were seen in seven (50%) patients obscuring the presence of apoptosis. The absence of Paneth cells, goblet cells or both was noted in seven (50%) patients. Follow-up information was available for all patients with 13 (93%) receiving immunosuppressant therapy and demonstrating partial-to-complete response. In total, three patients died from continued diarrhea and sepsis with one decedent before treatment could be initiated. In summary, autoimmune enteropathy in children is a heterogenous disease with protean clinical and pathologic findings. Although anti-enterocyte antibodies were identified in the majority of the cases, their presence was variable and insensitive. In addition, pediatric autoimmune enteropathy was frequently encountered in the setting of immunodeficiency disorders.

Diarrheal Illness in the Pediatric Population: A Review of Neonatal Enteropathies and Childhood Idiopathic Inflammatory Bowel Disease

In the clinical context of pediatric diarrheal illness, the interpretation of endoscopic mucosal biopsies varies significantly from that in adults. This review outlines these differences by first describing a host of diarrheal illnesses that are nearly exclusive to the pediatric age group. The final portion of this article describes salient pathologic differences between adult and pediatric idiopathic inflammatory bowel disease. The goal of this review is to provide a brief description of each disease process and focus on practical aspects of diagnosis that are applicable for pathologists working in general practice settings.