Inflammatory bowel disease caused by primary immunodeficiencies-Clinical presentations, review of literature, and proposal of a rational diagnostic algorithm

Gastrointestinal Disease in Common Variable Immunodeficiency Disorder (CVID): Histological Patterns, Diagnostic Clues and Pitfalls for the Pathologist and Gastroenterologist

Background/Objectives: Gastrointestinal diseases are a major cause of morbidity in common variable immunodeficiency disorder (CVID), clinically often mimicking other conditions including celiac disease and inflammatory bowel disease (IBD). Hence, diagnosis of CVID remains challenging. This study aims to raise awareness and highlight histopathological clues for CVID in intestinal biopsies, emphasizing diagnostic pitfalls for the pathologist/gastroenterologist. Methods: We reviewed 63 (18 duodenal, 23 ileal, 22 colonic) biopsies and case histories from seven CVID patients, obtained over a 31-year period, with attention to active inflammation, intraepithelial lymphocytes, plasma cells, lymphoid hyperplasia, crypt/villous architecture, subepithelial collagen, apoptosis, granulomas, and infections. Clinical information of 41 pathology requests was reviewed. Results: Gastrointestinal symptoms were variable. Histological features included IBD-like (3/7), celiac disease-like (2/7), graft-versus-host disease (GVHD)-like (2/7), lymphocytic sprue/colitis-like (3/7), collagenous colitis-like (2/7), and acute colitis-like (4/7) patterns, often overlapping (2/7) and/or changing over time (3/7). Lymphoid hyperplasia was seen in 3/7 patients; 1/7 had giardiasis; and 5/7 had few plasma cells, usually only in part of the gut (3/5). Clinical information of 12/41 (29%) pathology requests mentioned known/suspected CVID, despite being known in 33/41 (80%). Conclusions: Clinical/histological features of CVID in the gut are diverse, often mimicking IBD, microscopic colitis, celiac disease and/or GVHD, hence the importance of adequate clinical information. Some histological features are atypical of these established entities and may indicate CVID, as may overlapping/changing histological patterns and/or few plasma cells in part of the gut. Awareness of the heterogenous clinical presentation and histopathological indicators of CVID may improve diagnosis.

LRBA, a BEACH protein mutated in human immune deficiency, is widely expressed in epithelia, exocrine and endocrine glands, and neurons

Mutations in LRBA, a BEACH domain protein, cause severe immune deficiency in humans. LRBA is expressed in many tissues and organs according to biochemical analysis, but little is known about its cellular and subcellular localization, and its deficiency phenotype outside the immune system. By LacZ histochemistry of Lrba gene-trap mice, we performed a comprehensive survey of LRBA expression in numerous tissues, detecting it in many if not all epithelia, in exocrine and endocrine cells, and in subpopulations of neurons. Immunofluorescence microscopy of the exocrine and endocrine pancreas, salivary glands, and intestinal segments, confirmed these patterns of cellular expression and provided information on the subcellular localizations of the LRBA protein. Immuno-electron microscopy demonstrated that in neurons and endocrine cells, which co-express LRBA and its closest relative, neurobeachin, both proteins display partial association with endomembranes in complementary, rather than overlapping, subcellular distributions. Prominent manifestations of human LRBA deficiency, such as inflammatory bowel disease or endocrinopathies, are believed to be primarily due to immune dysregulation. However, as essentially all affected tissues also express LRBA, it is possible that LRBA deficiency enhances their vulnerability and contributes to the pathogenesis.

B cell-mediated CD4 T-cell costimulation via CD86 exacerbates pro-inflammatory cytokine production during autoimmune intestinal inflammation

Dysregulated B cell responses have been described in inflammatory bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for the detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified clusters of differentiation (CD)86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking costimulatory signals mediated by CD86 through cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially interferon-g (IFN-g) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression upregulated on activated B cells isolated from inflamed tissue of human patients with IBD. B cell activation and CD86 expression were boosted by soluble CD40L in vitro, which we found in the serum of mice and human patients with IBD. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.

Genetic Defects in Early-Onset Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) represents a spectrum of disease, which is characterized by chronic gastrointestinal inflammation. Monogenic mutations driving IBD pathogenesis are more highly represented in early-onset compared to adult-onset disease. The pathogenic genes which dysregulate host immune responses in monogenic IBD affect both the innate (ie, intestinal barrier, phagocytes) and adaptive immune systems (ie, T cells, B cells). Advanced genomic and targeted functional testing can improve clinical decision making and present increased opportunities for precision medicine approaches in this important patient population.

Higher Prevalence of Monogenic Cause Among Very Early Onset Inflammatory Bowel Disease in Children: Experience From a Tertiary Care Center From Northern India

BACKGROUND

Very early-onset inflammatory bowel disease (VEO-IBD) is generally defined as onset of IBD at <6 years of age. Up to 20% of VEO-IBD may have a monogenic cause; hence, next-generation sequencing is highly recommended for diagnostic accuracy. There remains a paucity of data on VEO-IBD and the proportion of monogeneic causes in South Asia. We analyzed our tertiary care center experience of monogenic VEO-IBD from Northern India and compared them with nonmonogenic VEO-IBD to find out the factors that differentiate monogenic from nonmonogenic VEO-IBD.

METHODS

All children (<18 years of age) diagnosed with IBD between January 2010 to July 2021 were analyzed along with the next-generation sequencing data and functional assays when available. Clinical features and outcomes between monogenic and nonmonogenic VEO-IBD were compared.

RESULTS

A total of 200 children with a median age of 15.3 (range, 0.17-17) years, 125 of whom were boys, were diagnosed to have IBD during the study period. VEO-IBD was seen in 48 (24%) children. Monogenic IBD was diagnosed in 15 (31%) children with VEO-IBD and 7.5% of all IBD cases. The causes of monogenic VEO-IBD included disorders of the immune system (including interleukin-10 receptor mutations) in 12 and epithelial barrier dysfunction in 3. Features that differentiated monogenic from nonmonogenic VEO-IBD were neonatal IBD, presence of perianal disease, IBD unclassified, history of consanguinity and sibling death, wasting, and stunting (P < .05). There were 6 deaths.

CONCLUSIONS

One-third of participants were monogenic among Indian children with VEO-IBD, the highest proportion reported to date in the world. Next-generation (either exome or whole genome) sequencing should be recommended in a subset of VEO-IBD with neonatal onset, perianal disease, history of consanguinity and siblings' death, wasting, stunting, and IBD unclassified phenotype for an early diagnosis and referral to an appropriate center for hematopoietic stem cell transplantation for a better outcome.

Consenso colombiano de la enfermedad inflamatoria intestinal pediátrica

Introducción: la colitis ulcerativa pediátrica (CUP), la enfermedad de Crohn pediátrica (ECP) y la enfermedad inflamatoria intestinal pediátrica no clasificable (EIIPNC) tienen particularidades clínicas y psicosociales que las diferencian de las del adulto y pueden condicionar enfoques terapéuticos distintos por las posibles repercusiones nutricionales, crecimiento y desarrollo, lo que representa un desafío para el pediatra y el gastroenterólogo. Objetivo: desarrollar recomendaciones basadas en la evidencia por consenso de expertos para el diagnóstico y el tratamiento oportunos y seguros de la enfermedad inflamatoria intestinal pediátrica (EIIP) en menores de 18 años, para los profesionales que atienden estos pacientes y los pagadores en salud. Metodología: a través de un panel de expertos del Colegio Colombiano de Gastroenterología, Hepatología y Nutrición Pediátrica (COLGAHNP) y un grupo multidisciplinario se formularon 35 preguntas en relación con el cuadro clínico, el diagnóstico y el tratamiento de la EIIP. A través de una revisión y un análisis crítico de la literatura, con especial énfasis en las principales guías de práctica clínica (GPC), estudios clínicos aleatorizados (ECA) y metaanálisis de los últimos 10 años, los expertos plantearon 77 recomendaciones que respondían a cada una de las preguntas de investigación con sus respectivos puntos prácticos. Posteriormente, cada una de las afirmaciones se sometieron a votación dentro del grupo desarrollador, incluyendo las afirmaciones que alcanzaron > 80 %. Resultados: todas las afirmaciones alcanzaron una votación > 80 %. La EIIP tiene mayor extensión, severidad y evolución hacia la estenosis, enfermedad perianal, manifestaciones extraintestinales y retraso en el crecimiento en comparación con los pacientes adultos, por lo que su manejo debe ser realizado por grupos multidisciplinarios liderados por gastroenterólogos pediatras y prepararlos para una transición a la edad adulta. Los criterios de Porto permiten una clasificación práctica de la EIIP. En la ECP, debemos usar la clasificación de París y debemos realizar ileocolonoscopia y esofagogastroduodenoscopia, ya que el 50 % tienen un compromiso superior, usando el SES-CD (UCEIS/Mayo en CUP) y tomando múltiples biopsias. Los laboratorios iniciales deben incluir marcadores de inflamación, calprotectina fecal y descartar infecciones intestinales. El tratamiento, la inducción y el mantenimiento de la EIIP deben ser individualizados y decididos según la estratificación de riesgo. En el seguimiento se debe usar el Pediatric Crohn Disease Activity Index (PCDAI) y Pediatric Ulcerative Colitis Activity Index (PUCAI) de las últimas 48 horas. Los pacientes con EIIP temprana e infantil, deben ser valorados por inmunólogos y genetistas. Conclusión: se proporciona una guía de consenso con recomendaciones basadas en la evidencia sobre el diagnóstico y los tratamientos oportunos y seguros en los pacientes con EIIP.

Checkpoint Inhibitor-Induced Colitis: From Pathogenesis to Management

The advent of immunotherapy, specifically of immune checkpoint inhibitors (ICIs), for the treatment of solid tumors has deeply transformed therapeutic algorithms in medical oncology. Approximately one-third of patients treated with ICIs may de velop immune-related adverse events, and the gastrointestinal tract is often affected by different grades of mucosal inflammation. Checkpoint inhibitors colitis (CIC) presents with watery or bloody diarrhea and, in the case of severe symptoms, requires ICIs discontinuation. The pathogenesis of CIC is multifactorial and still partially unknown: anti-tumor activity that collaterally effects the colonic tissue and the upregulation of specific systemic inflammatory pathways (i.e., CD8+ cytotoxic and CD4+ T lymphocytes) are mainly involved. Many questions remain regarding treatment timing and options, and biological treatment, especially with anti-TNF alpha, can be offered to these patients with the aim of rapidly resuming oncological therapies. CIC shares similar pathogenesis and aspects with inflammatory bowel disease (IBD) and the use of ICI in IBD patients is under evaluation. This review aims to summarize the pathogenetic mechanism underlying CIC and to discuss the current evidenced-based management options, including the role of biological therapy, emphasizing the relevant clinical impact on CIC and the need for prompt recognition and treatment.

Primary Immunodeficiencies in Children Initially Admitted with Gastrointestinal/Liver Manifestations

Purpose

The gastrointestinal system is the most commonly affected organ, followed by the lungs, in patients with primary immunodeficiency disease (PID). Hence, it is common for children with PIDs to present with gastrointestinal symptoms. We aimed to analyze the clinical and histopathological findings of patients who were initially admitted to pediatric gastroenterology/hepatology clinics and subsequently diagnosed with PIDs to identify the clinical clues for PIDs.

Methods

The demographic, laboratory, and histopathological findings, treatment modality, and outcomes of patients initially admitted to the pediatric gastroenterology/hepatology unit and subsequently diagnosed with PIDs were recorded.

Results

The study included 24 patients (58.3% male; median age [range]: 29 [0.5-204] months). Common clinical presentations included chronic diarrhea (n=8), colitis (n=6), acute hepatitis (n=4), and acute liver failure (n=2). The association of autoimmune diseases, development of malignant diseases, and severe progression of viral diseases was observed in 20.8%, 8.3%, and 16.6% of the patients, respectively. Antibody deficiency was predominantly diagnosed in 29.2% of patients, combined immunodeficiency in 20.8%, immune dysregulation in 12.5%, defects in intrinsic and innate immunity in 4.2%, autoinflammatory disorders in 8.3%, and congenital defects of phagocytes in 4.2%. Five patients remained unclassified (20.8%).

Conclusion

Patients with PIDs may initially experience gastrointestinal or liver problems. It is recommended that the association of autoimmune or malignant diseases or severe progression of viral diseases provide pediatric gastroenterologists some suspicion of PIDs. After screening using basic laboratory tests, genetic analysis is mandatory for a definitive diagnosis.

Immune Checkpoint Inhibitor Enterocolitis vs Idiopathic Inflammatory Bowel Disease

Immune checkpoint inhibitors have revolutionized management of advanced malignancies. However, their use is frequently complicated by immune related adverse events (irAEs), immune checkpoint inhibitor enterocolitis (IMEC) being the most common toxicity. IMEC is a distinct form of bowel inflammation that is highly reminiscent of idiopathic inflammatory bowel disorders (Crohn's disease, ulcerative colitis, and microscopic colitis). In this review, we highlight the similarities and differences in the pathophysiology, clinical presentation, evaluation, and management of these overlapping immune inflammatory bowel disorders. IMEC is an inflammatory bowel disease-like irAE that occurs as an outcome of disruption of intestinal immune surveillance and gut dysbiosis. Clinical and endoscopic presentation of both entities is strikingly similar, which often guides management. Though well established in inflammatory bowel disease, little is known about the long term outcomes of IMEC.

Treatment of inborn errors of immunity patients with inflammatory bowel disease phenotype by allogeneic stem cell transplantation

Patients with inborn errors of immunity (IEI) can suffer from treatment-refractory inflammatory bowel disease (IBD) causing failure to thrive and consequences of long-term multiple immunosuppressive treatments. Allogeneic haematopoietic stem cell transplantation (alloHSCT) can serve as a curative treatment option. In this single-centre retrospective cohort study we report on 11 paediatric and young adult IEI patients with IBD and failure to thrive, who had exhausted symptomatic treatment options and received alloHSCT. The cohort included chronic granulomatous disease (CGD), lipopolysaccharide-responsive and beige-like anchor protein (LRBA) deficiency, STAT3 gain-of-function (GOF), Wiskott-Aldrich syndrome (WAS), dedicator of cytokinesis 8 (DOCK8) deficiency and one patient without genetic diagnosis. All patients achieved stable engraftment and immune reconstitution, and gastrointestinal symptoms were resolved after alloHSCT. The overall survival was 11/11 over a median follow-up of 34.7 months. Graft-versus-host disease (GVHD) was limited to grade I-II acute GVHD (n = 5), one case of grade IV acute GVHD and one case of limited chronic GVHD. Since treatment recommendations are limited, this work provides a centre-specific approach to treatment prior to transplant as well as conditioning in IEI patients with severe IBD.

Protein-losing Enteropathy as a Complication and/or Differential Diagnosis of Common Variable Immunodeficiency

As protein-losing enteropathy (PLE) can lead to hypogammaglobulinemia and lymphopenia, and since common variable immunodeficiency (CVID) is associated with digestive complications, we wondered if (1) PLE could occur during CVID and (2) specific features could help determine whether a patient with antibody deficiency has CVID, PLE, or both. Eligible patients were thus classified in 3 groups: CVID + PLE (n = 8), CVID-only (= 19), and PLE-only (n = 13). PLE was diagnosed using fecal clearance of α1-antitrypsin or 111In-labeled albumin. Immunoglobulin (Ig) A, G, and M, naive/memory B and T cell subsets were compared between each group. CVID + PLE patients had multiple causes of PLE: duodenal villous atrophy (5/8), nodular follicular hyperplasia (4/8), inflammatory bowel disease-like (4/8), portal hypertension (4/8), giardiasis (3/8), and pernicious anemia (1/8). Compared to the CVID-only group, CVID + PLE patients had similar serum Ig levels, B cell subset counts, but lower naive T cell proportion and IgG replacement efficiency index. Compared to the CVID-only group, PLE-only patients did not develop infections but had higher serum levels of IgG (p = 0.03), IgA (p < 0.0001), and switched memory B cells (p = 0.001); and decreased naive T cells (CD4⁺: p = 0.005; CD8⁺: p < 0.0001). Compared to the PLE-only group, CVID + PLE patients had higher infection rates (p = 0.0003), and lower serum Ig (especially IgA: p < 0.001) and switched memory B cells levels. In conclusion, PLE can occur during CVID and requires higher IgG replacement therapy dosage. PLE can also mimic CVID and is associated with milder immunological abnormalities, notably mildly decreased to normal serum IgA and switched memory B cell levels.

Inborn errors of immunity and related microbiome

Inborn errors of immunity (IEI) are characterized by diverse clinical manifestations that are dominated by atypical, recurrent, chronic, or severe infectious or non-infectious features, including autoimmunity, lymphoproliferative disease, granulomas, and/or malignancy, which contribute substantially to morbidity and mortality. Some data suggest a correlation between clinical manifestations of IEI and altered gut microbiota. Many IEI display microbial dysbiosis resulting from the proliferation of pro-inflammatory bacteria or a decrease in anti-inflammatory bacteria with variations in the composition and function of numerous microbiota. Dysbiosis is considered more established, mainly within common variable immunodeficiency, selective immunoglobulin A deficiency, severe combined immunodeficiency diseases, Wiskott–Aldrich syndrome, Hyper-IgE syndrome, autoimmune polyendocrinopathy–candidiasis–ectodermal-dystrophy (APECED), immune dysregulation, polyendocrinopathy, enteropathy X-linked (IPEX) syndrome, IL-10 receptor deficiency, chronic granulomatous disease, and Kostmann disease. For certain IEIs, the specific predominance of gastrointestinal, respiratory, and cutaneous involvement, which is frequently associated with dysbiosis, justifies the interest for microbiome identification. With the better understanding of the relationship between gut microbiota, host immunity, and infectious diseases, the integration of microbiota modulation as a therapeutic approach or a preventive measure of infection becomes increasingly relevant. Thus, a promising strategy is to develop optimized prebiotics, probiotics, postbiotics, and fecal microbial transplantation to rebalance the intestinal microbiota and thereby attenuate the disease activity of many IEIs.

Very Early Onset-IBD: evidence for the need of a multidisciplinary approach

Very early onset inflammatory bowel disease (VEO-IBD) represents approximately 25% of cases of IBD-like colitis occurring during childhood and, by definition, it is characterized by an onset prior to 6 years of age. This subgroup of patients presents significant differences from IBD occurring in older children and in adults, including a more severe clinical course, a reduced responsiveness to conventional IBD therapy, and a greater proportion of cases featuring an underlying monogenic disorder. Histological findings from gastro-intestinal (GI) biopsies are characterized by an IBD-like, apoptotic or enterocolitis-like pattern, complicating the differential diagnosis with other pediatric diseases involving GI tract. Moreover, individuals with monogenic disorders may develop significant comorbidities, such as primary immunodeficiency (PID), impacting treatment options. Without an appropriate diagnosis, the clinical course of VEO-IBD has greater potential for escalated treatment regimens involving extensive surgery, more intensive medical therapies and, even more important, inadequate recognition of underlying monogenic defect that may lead to inappropriate (sometimes fatal) therapy. For these reasons, an adequate context leading to an appropriate diagnosis is imperative, calling for a close collaboration between pediatricians, pathologists, geneticists, and immunologists.

Primary Hypogammaglobulinaemia with Inflammatory Bowel Disease-Like Features: An ECCO CONFER Multicentre Case Series

BACKGROUND

Hypogammaglobulinaemia is a disorder characterized by low serum immunoglobulin levels and a high prevalence of gastrointestinal manifestations. In some cases, clinical and endoscopic features are indistinguishable from those of inflammatory bowel disease [IBD].

METHODS

This was a multicentre case series performed as a part of the European Crohn's and Colitis Organisation [ECCO] Collaborative Network of Exceptionally Rare case reports [CONFER] project.

RESULTS

This report includes 27 patients with primary hypogammaglobulinaemia and IBD-like features: 20 males and seven females, median age 45.6 years (interquartile range [IQR] 35.2-59). Crohn's disease-like features were noted in 23 patients, and four patients had ulcerative colitis-like features. The diagnosis of hypogammaglobulinaemia preceded a diagnosis of IBD-like features in 20 patients [median of 7 years prior, IQR 2.6-20.6 years], and followed the appearance of IBD-like features in seven cases [median of 1 year after, IQR 0.45-5.6 years]. Hypogammaglobulinaemia aetiologies were common variable immunodeficiency [66.6%], agammaglobulinaemia [7.4%], selective IgA-deficiency [11.1%], Good's syndrome [7.4%], IgG subclass deficiency with IgA deficiency [3.7%] and hyper-IgM [3.7%]. In addition to antibiotics and intravenous immunoglobulin [IVIG] for hypogammaglobulinaemia, 12 patients received IBD-related treatment including 5-aminosalicylate agents [two patients], corticosteroids [one patient], thiopurines [three patients], anti-tumour necrosis factor [four patients] and vedolizumab [two patients]. By the end of the follow-up (44.5 months [IQR 18-81]), 21/27 [77%] patients were in clinical remission.

CONCLUSION

This case series describes IBD-like features in patients with hypogammaglobulinaemia. The diagnosis of IBD-like features mainly occurred after that of hypogammaglobulinaemia, with successful recovery in the majority of cases after appropriate treatment.

Intestinal outcome of bone marrow transplantation for monogenic inflammatory bowel disease

BACKGROUND

Some monogenic inflammatory bowel diseases (IBDs) are known to be refractory to conventional treatments. Although allogeneic hematopoietic stem-cell transplantation (allo-HSCT) has become a curative therapeutic option for certain monogenic IBDs, its effectiveness regarding endoscopic improvements has not been clarified.

METHODS

The clinical course and endoscopic findings of patients with monogenic IBDs who were treated with allo-HSCT between December 2017 and November 2018 at the National Center for Child Health and Development, were retrospectively reviewed. The clinical disease activity was assessed using the weighted Pediatric Crohn's Disease Activity Index (wPCDAI) and the endoscopic finding was evaluated using the Simple Endoscopic Score for Crohn's Disease (SES-CD). Clinical remission was defined as a wPCDAI <10 and endoscopic remission was defined as an SES-CD of 2 or less.

RESULTS

Four patients with severe monogenic IBDs, including three with X-linked inhibitors of apoptosis protein (XIAP) deficiency and one with interleukin-10 signaling defect, were treated with allo-HSCT with reduced-intensity conditioning. In four patients, the maximum scores of wPCDAI and SES-CD before allo-HSCT ranged from 67.5 to 120 and 20 to 34, respectively. After allo-HSCT, all four patients showed a significant improvement in intestinal inflammation and achieved both clinical and endoscopic remission. Although patients with XIAP deficiency presented with post-transplant hemophagocytic lymphohistiocytosis and a relatively late engraftment, all patients achieved prolonged clinical remission, and IBD medications were successfully discontinued in all patients.

CONCLUSION

Allo-HSCT for monogenic IBD resulted in complete clinical resolution with endoscopically confirmed mucosal healing.

Immunological Networks Defining the Heterogeneity of Inflammatory Bowel Diseases

Current practice in IBD is to classify patients based on clinical signs and symptoms and provide treatments accordingly. However, the response of IBD patients to available treatments is highly variable, highlighting clinically significant heterogeneity among patients. Thus, more accurate patient stratification is urgently needed to more effectively target therapeutic interventions to specific patients. Here we review the degree of heterogeneity in IBD, discussing how the microbiota, genetics, and immune system may contribute to the variation among patients. We highlight how molecular heterogeneity may relate to clinical phenotype, but in other situations may be independent of clinical phenotype, encouraging future studies to fill the gaps. Finally, we discuss novel stratification methodologies as a foundation for precision medicine, in particular a novel stratification strategy based on conserved genes across species. All of these dimensions of heterogeneity have potential to provide strategies for patient stratification and move IBD practice towards personalised medicine.

Needs for Increased Awareness of Gastrointestinal Manifestations in Patients With Human Inborn Errors of Immunity

The gastrointestinal (GI) tract is frequently affected by inborn errors of immunity (IEI), and GI manifestations can be present in IEI patients before a diagnosis is confirmed. We aimed to investigate clinical features, endoscopic and histopathologic findings in IEI patients. This was a retrospective cohort study conducted from 1995 to 2020. Eligible patients were diagnosed with IEI and had GI manifestations that were enough to require endoscopies. IEI was classified according to the International Union of Immunological Societies classification. Of 165 patients with IEI, 55 (33.3%) had GI manifestations, and 19 (11.5%) underwent endoscopy. Among those 19 patients, nine (47.4%) initially presented with GI manifestations. Thirteen patients (68.4%) were male, and the mean age of patients 11.5 ± 7.9 years (range, 0.6 – 26.6) when they were consulted and evaluated with endoscopy. The most common type of IEI with severe GI symptoms was “Disease of immune dysregulation” (31.6%) followed by “Phagocyte defects” (26.3%), according to the International Union of Immunological Societies classification criteria. Patients had variable GI symptoms such as chronic diarrhea (68.4%), hematochezia (36.8%), abdominal pain (31.6%), perianal disease (10.5%), and recurrent oral ulcers (10.5%). During the follow-up period, three patients developed GI tract neoplasms (early gastric carcinoma, mucosa associated lymphoid tissue lymphoma of colon, and colonic tubular adenoma, 15.8%), and 12 patients (63.2%) were diagnosed with inflammatory bowel disease (IBD)-like colitis. Investigating immunodeficiency in patients with atypical GI symptoms can provide an opportunity for correct diagnosis and appropriate disease-specific therapy. Gastroenterologists and immunologists should consider endoscopy when atypical GI manifestations appear in IEI patients to determine if IBD-like colitis or neoplasms including premalignant and malignant lesions have developed. Also, if physicians in various fields are better educated about IEI-specific complications, early diagnosis and disease-specific treatment for IEI will be made possible.

Immune checkpoint inhibitor-mediated colitis in gastrointestinal malignancies and inflammatory bowel disease

Immune checkpoint inhibitors (ICI) have markedly changed the landscape of cancer therapy. By re-invigorating the immune system against tumors, ICI provide novel therapeutic options for a broad variety of malignancies, including many gastrointestinal (GI) cancers. However, these therapies can also induce autoimmune-like side effects in healthy tissue across the body. One of the most common of these side effects is ICI-mediated colitis and diarrhea (IMC). Here, we review the incidence and risk of IMC in ICI therapy, with a focus on what is known regarding IMC in patients with GI malignancies. We also discuss data available on the use of ICI and risk of IMC in patients with pre-existing inflammatory bowel disease, as these patients may have increased risk of IMC due to their underlying intestinal pathology.

Clinical Genomics for the Diagnosis of Monogenic Forms of Inflammatory Bowel Disease: A Position Paper From the Paediatric IBD Porto Group of European Society of Paediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND

It is important to identify patients with monogenic IBD as management may differ from classical IBD. In this position statement we formulate recommendations for the use of genomics in evaluating potential monogenic causes of IBD across age groups.

METHODS

The consensus included paediatric IBD specialists from the Paediatric IBD Porto group of the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and specialists from several monogenic IBD research consortia. We defined key topics and performed a systematic literature review to cover indications, technologies (targeted panel, exome and genome sequencing), gene panel setup, cost-effectiveness of genetic screening, and requirements for the clinical care setting. We developed recommendations that were voted upon by all authors and Porto group members (32 voting specialists).

RESULTS

We recommend next-generation DNA-sequencing technologies to diagnose monogenic causes of IBD in routine clinical practice embedded in a setting of multidisciplinary patient care. Routine genetic screening is not recommended for all IBD patients. Genetic testing should be considered depending on age of IBD-onset (infantile IBD, very early-onset IBD, paediatric or young adult IBD), and further criteria, such as family history, relevant comorbidities, and extraintestinal manifestations. Genetic testing is also recommended in advance of hematopoietic stem cell transplantation. We developed a diagnostic algorithm that includes a gene panel of 75 monogenic IBD genes. Considerations are provided also for low resource countries.

CONCLUSIONS

Genomic technologies should be considered an integral part of patient care to investigate patients at risk for monogenic forms of IBD.

Case Report: Refractory Autoimmune Gastritis Responsive to Abatacept in LRBA Deficiency

Primary immunodeficiency (PID) with immune dysregulation may present with early onset gastrointestinal autoimmune disorders. When gastrointestinal autoimmunity is associated with multiple extraintestinal immune system dysfunction the diagnosis of PID is straightforward. However, with the advent of next generation sequencing technologies, genetic defects in PID genes have been increasingly recognized even when a single or no extraintestinal signs of immune dysregulation are present. A genetic diagnosis is especially important considering the expanding armamentarium of therapies designed to inhibit specific molecular pathways. We describe a boy with early-onset severe, refractory autoimmune gastritis and biallelic mutations in the LRBA gene causing a premature STOP-codon who was successfully treated with CTLA4-Ig, abatacept, with long term clinical and endoscopic remission. The case underscores the importance to consider a monogenetic defect in early onset autoimmune disorders, since the availability of targeted treatments may significantly improve patient prognosis.

Knockout-Induced Pluripotent Stem Cells for Disease and Therapy Modeling of IL-10-Associated Primary Immunodeficiencies

Samples from patients with rare diseases, such as primary immunodeficiencies, are often limited, which hampers careful analysis of the pathomechanisms involved in immune cell dysregulation. To overcome this issue, induced pluripotent stem cells (iPSCs) represent an almost inexhaustible cell source and thus provide an excellent opportunity to generate disease models for rare diseases and to validate new therapeutic approaches. To obtain a better understanding of primary immunodeficiencies associated with the interleukin (IL)-10 signaling pathway, for example, very-early-onset inflammatory bowel disease (VEO-IBD), we generated genetic knockouts (KOs) of IL-10RA (IL-10 receptor α-chain) and IL-10RB (IL-10 receptor β-chain) as well as the downstream targets of the IL-10-receptor (IL-10R) signal transducers and activators of transcription (STAT)1 and STAT3 via an sgRNA (single-guide RNA)-CRISPR-Cas9-expressing lentiviral system. IL-10 signaling-associated KO models and a VEO-IBD patient-derived iPSC clone were differentiated into macrophages for disease models. IL-10R- or STAT3-deficient disease models showed no IL-10-induced BCL3 or SOCS3 expression, whereas lipopolysaccharide (LPS) stimulation induced IL-10R independently of BCL3 and SOCS3 expression. Cytokine secretion profiles from iPSC-derived macrophage disease models showed that IL-10 was involved in many inflammatory cytokine secretions, which indicated formation of both anti- and proinflammatory macrophage phenotypes. Macrophage-secreted cytokines were separated into IL-10R- and STAT3-dependent (IL-6, TNF-α), or into IL-10R-, STAT1-, and STAT3-dependent cytokines (CCL2, CXCL10). Importantly, lentiviral correction restored IL-10-mediated regulation of LPS-induced cytokine secretion in corrected IL-10RB, STAT1, and VEO-IBD patient-derived disease models. Furthermore, treatment of IL-10RB-deficient macrophages with anti-inflammatory small molecules (SB202190, filgotinib) reduced proinflammatory cytokine secretion patterns. Taken together, the described iPSC KO models gave new insights into the pathomechanisms of immune cell dysregulation and served as model systems to test potential therapeutic approaches, including lentiviral gene therapy and targeted small-molecule treatment.

IBDs and the pediatric age: Their peculiarities and the involvement of the microbiota

Inflammatory Bowel Diseases (IBDs) are gastrointestinal disorders characterized by chronic, relapsing inflammation, with growing incidence worldwide over the last decades and distinctive features in the pediatric age. An increasing body of evidence indicates that gut microbiota plays a major role in inflammatory disorders, including IBDs. In this review we will discuss the most recent evidences on dysbiotic changes associated with gut inflammation, as well as environmental and genetic factors contributing to IBD pathogenesis, with a focus on the peculiarities of the pediatric age.

Association of Primary Humoral Immunodeficiencies With Psychiatric Disorders and Suicidal Behavior and the Role of Autoimmune Diseases

IMPORTANCE

The hypothesis that disrupted immune function is implicated in the pathophysiology of psychiatric disorders and suicide is gaining traction, but the underlying mechanisms are largely unknown. Primary humoral immunodeficiencies (PIDs) are rare deficiencies of the immune system-mainly dysfunction of antibody production-and are associated with adverse health problems, such as recurrent infections and autoimmune diseases.

OBJECTIVE

To establish whether PIDs that affect antibody function and level are associated with lifetime psychiatric disorders and suicidal behavior and whether this association is explained by the co-occurrence of autoimmune diseases.

DESIGN, SETTING, AND PARTICIPANTS

This population- and sibling-based cohort study included more than 14 million individuals living in Sweden from January 1, 1973, through December 31, 2013. Register-based data on exposure, outcomes, and covariates were collected through December 31, 2013. Individuals with a record of PID were linked to their full siblings, and a family identification number was created. Data were analyzed from May 17, 2019, to February 21, 2020.

EXPOSURES

Lifetime records of PID and autoimmune disease.

MAIN OUTCOMES AND MEASURES

Lifetime records of 12 major psychiatric disorders and suicidal behavior, including suicide attempts and death by suicide.

RESULTS

A lifetime diagnosis of PID affecting immunoglobulin levels was identified in 8378 patients (4947 women [59.0%]; median age at first diagnosis, 47.8 [interquartile range, 23.8-63.4] years). A total of 4776 clusters of full siblings discordant for PID was identified. After adjusting for comorbid autoimmune diseases, PIDs were associated with greater odds of any psychiatric disorder (adjusted odds ratio [AOR], 1.91; 95% CI, 1.81-2.01) and any suicidal behavior (AOR, 1.84; 95% CI, 1.66-2.04). The associations were also significant for all individual psychiatric disorders (range of AORs, 1.34 [95% CI, 1.17-1.54] for schizophrenia and other psychotic disorders to 2.99 [95% CI, 2.42-3.70] for autism spectrum disorders), death by suicide (AOR, 1.84; 95% CI, 1.25-2.71), and suicide attempts (AOR, 1.84; 95% CI, 1.66-2.04). In the sibling comparisons, the associations were attenuated but remained significant for aggregated outcomes (AOR for any psychiatric disorder, 1.64 [95% CI, 1.48-1.83]; AOR for any suicidal behavior, 1.37 [95% CI, 1.14-1.66]), most individual disorders (range of AORs, 1.46 [95% CI, 1.23-1.73] for substance use disorders to 2.29 [95% CI, 1.43-3.66] for autism spectrum disorders), and suicide attempts (AOR, 1.41; 95% CI, 1.17-1.71). Joint exposure for PID and autoimmune disease resulted in the highest odds for any psychiatric disorder (AOR, 2.77; 95% CI, 2.52-3.05) and any suicidal behavior (AOR, 2.75; 95% CI, 2.32-3.27). The associations with psychiatric outcomes (AORs, 2.42 [95% CI, 2.24-2.63] vs 1.65 [95% CI, 1.48-1.84]) and suicidal behavior (AORs, 2.43 [95% CI, 2.09-2.82] vs 1.40 [95% CI, 1.12-1.76]) were significantly stronger for women than for men with PID.

CONCLUSIONS AND RELEVANCE

Primary humoral immunodeficiencies were robustly associated with psychopathology and suicidal behavior, particularly in women. The associations could not be fully explained by co-occurring autoimmune diseases, suggesting that antibody dysfunction may play a role, although other mechanisms are possible. Individuals with both PID and autoimmune disease had the highest risk of psychiatric disorders and suicide, suggesting an additive effect. Future studies should explore the underlying mechanisms of these associations.

TNF Receptor 1 Promotes Early-Life Immunity and Protects against Colitis in Mice

Neutralization of tumor necrosis factor (TNF) represents a widely used therapeutic strategy for autoimmune diseases including inflammatory bowel disease (IBD). However, the fact that many patients with IBD are non-responsive to anti-TNF therapies suggests the need for a better understanding of TNF signaling in IBD. Here, we show that co-deletion of TNF receptor 1 (TNFR1, Tnfrsf1a) in the Il10^-/- spontaneous colitis model exacerbates disease, resulting in very-early-onset inflammation after weaning. The disease can be interrupted by treatment with antibiotics. The single deletion of TNFR1 induces subclinical colonic epithelial dysfunction and mucosal immune abnormalities, including accumulation of neutrophils and depletion of B cells. During the pre-disease period (before weaning), both Tnfr1^-/- and Il10^-/-Tnfr1^-/- animals exhibit impaired expression of pro-inflammatory cytokines compared with wild-type and Il10^-/- controls, respectively. Collectively, these results demonstrate the net anti-inflammatory functions of TNF/TNFR1 signaling through the regulation of colonic immune homeostasis in early life.

Primary Humoral Immune Deficiencies: Overlooked Mimickers of Chronic Immune-Mediated Gastrointestinal Diseases in Adults

In recent years, the incidence of immune-mediated gastrointestinal disorders, including celiac disease (CeD) and inflammatory bowel disease (IBD), is increasingly growing worldwide. This generates a need to elucidate the conditions that may compromise the diagnosis and treatment of such gastrointestinal disorders. It is well established that primary immunodeficiencies (PIDs) exhibit gastrointestinal manifestations and mimic other diseases, including CeD and IBD. PIDs are often considered pediatric ailments, whereas between 25 and 45% of PIDs are diagnosed in adults. The most common PIDs in adults are the selective immunoglobulin A deficiency (SIgAD) and the common variable immunodeficiency (CVID). A trend to autoimmunity occurs, while gastrointestinal disorders are common in both diseases. Besides, the occurrence of CeD and IBD in SIgAD/CVID patients is significantly higher than in the general population. However, some differences concerning diagnostics and management between enteropathy/colitis in PIDs, as compared to idiopathic forms of CeD/IBD, have been described. There is an ongoing discussion whether CeD and IBD in CVID patients should be considered a true CeD and IBD or just CeD-like and IBD-like diseases. This review addresses the current state of the art of the most common primary immunodeficiencies in adults and co-occurring CeD and IBD.

Patterns of mucosal inflammation in pediatric inflammatory bowel disease: striking overexpression of IL-17A in children with ulcerative colitis

BACKGROUND

Aberrant immune responses play a key role in the pathogenesis of inflammatory bowel disease (IBD). Most studies conducted to delineate the underlying molecular mechanisms focus on adults; an understanding of these mechanisms in children remains to be determined. Here, cytokines and transcription factors produced by immune cells within the intestinal mucosa of pediatric patients stricken with ulcerative colitis (UC) and Crohn's disease (CD) are characterized; potential diagnostic and therapeutic targets are identified.

METHODS

Fifty-two pediatric IBD and non-IBD patients were enrolled in the study. Specimens were taken during ileocolonoscopy. Expression of 16 genes that encode cytokines or transcription molecules was determined by quantitative polymerase chain reaction. Clinical data were collected via retrospective chart review.

RESULTS

Overexpression of interleukin-17A (IL-17A) was evident in children with UC compared to both non-IBD and CD patients. IL-22 was strongly increased in UC patients only. Typical proinflammatory and immunoregulatory cytokines were pronounced in IBD patients, although to a lower extent in the latter case. Clustered gene expression enabled differentiation between UC and non-IBD patients.

CONCLUSION

Our findings highlight the crucial involvement of IL-17A immunity in the early course of IBD, particularly UC, and the potential value of gene panels in diagnosing pediatric IBD.

Gastrointestinal Disorders Associated with Primary Immunodeficiency Diseases

There are now 354 inborn errors of immunity (primary immunodeficiency diseases (PIDDs)) with 344 distinct molecular etiologies reported according to the International Union of Immunological Sciences (IUIS) (Clin Gastroenterol Hepatol 11: p. 1050-63, 2013, Semin Gastrointest Dis 8: p. 22-32, 1997, J Clin Immunol 38: p. 96-128, 2018). Using the IUIS document as a reference and cross-checking PubMed ( www.ncbi.nlm.nih.pubmed.gov ), we found that approximately one third of the 354 diseases of impaired immunity have a gastrointestinal component [J Clin Immunol 38: p. 96-128, 2018]. Often, the gastrointestinal symptomatology and pathology is the heralding sign of a PIDD; therefore, it is important to recognize patterns of disease which may manifest along the gastrointestinal tract as a more global derangement of immune function. As such, holistic consideration of immunity is warranted in patients with clinically significant gastrointestinal disease. Here, we discuss the manifold presentations and GI-specific complications of PIDDs which could lead patients to seek advice from a variety of clinician specialists. Often, patients with these medical problems will engage general pediatricians, surgeons, gastroenterologists, rheumatologists, and clinical immunologists among others. Following delineation of the presenting concern, accurate and often molecular diagnosis is imperative and a multi-disciplinary approach warranted for optimal management. In this review, we will summarize the current state of understanding of PIDD gastrointestinal disease involvement. We will do so by focusing upon gastrointestinal disease categories (i.e., inflammatory, diarrhea, nodular lymphoid hyperplasia, liver/biliary tract, structural disease, and oncologic disease) with an intent to aid the healthcare provider who may encounter a patient with an as-yet undiagnosed PIDD who presents initially with a gastrointestinal symptom, sign, or problem.

Infections and malignancies risks related to TNF-α-blocking agents in pediatric inflammatory bowel diseases

Introduction: Tumor necrosis factor-α (TNF-α)-blocking agents are drugs approved for the treatment of inflammatory bowel diseases (IBDs). Infliximab and adalimumab are approved for the treatment of IBD in the pediatric setting with the improvement of therapeutic management. Biological agents, also in the pediatric population, can be administered either alone or in combination with immunomodulators. Their use has raised safety concerns regarding the risk of infections and malignancies.Areas covered: A broad review of the safety concerns for the use of anti-TNF-α drugs in children with IBD was performed, and information regarding the risk of infections and malignancies were updated, also in comparison with the safety of traditional drugs such as steroids and/or immunosuppressants.Expert commentary: Anti-TNF-α drugs have shown favorable safety profiles, and adalimumab treatment is associated with lower immunogenicity compared with infliximab. Heightened awareness and vigilant surveillance leading to prompt diagnosis and treatment are important for optimal management.

Primary Immunodeficiency and the Gut

This article presents the most common gastrointestinal, hepatic, and pancreatic manifestations of the primary immunodeficiency diseases, including the appropriate laboratory testing, endoscopic evaluation, and recommendations for further management.

Persisting enteropathy and disturbed adaptive mucosal immunity due to MHC class II deficiency

Intestinal epithelial cells (IECs) form a fundamental mucosal barrier and actively participate in tolerance and immunity against intestinal contents. Major histocompatibility complex class II (MHC II) and invariant chain (Ii) molecules are essential for adaptive immune response. MHC II deficiency often presents with gastrointestinal disorders. Intestinal biopsy samples revealed an absence of HLA-DR, Ii, and local immunoglobulins in both hematopoietic immune cells and IECs accompanied by a lack of faecal sIgA. After successful hematopoietic stem cell transplantation (HSCT) absent HLA-DR and Ii expression persisted in IECs and faecal stool analysis indicated inflammation and high microbial activity. We describe multifaceted disturbance of adaptive mucosal immunity in MHC II deficient patients suffering from enteropathy. HLA-DR and Ii expression on enterocytes is not restored by HSCT. This may account for increased susceptibility to enteric infections and intestinal inflammation leading to prolonged enteropathy reported in MHC II deficient patients.

Chlorogenic Acid Ameliorates Colitis and Alters Colonic Microbiota in a Mouse Model of Dextran Sulfate Sodium-Induced Colitis

This study evaluated the mitigating effects of dietary chlorogenic acid (CGA) on colon damage and the bacterial profile in a mouse model of dextran sulfate sodium (DSS)-induced colitis. C57BL/6J mice were randomly assigned to receive one of the following treatments: (i) basal diet; (ii) basal diet with 2% CGA; (iii) basal diet with 2.5% DSS or (iv) basal diet with 2% CGA and 2.5% DSS. Following a 2-week pre-treatment period, mice in the DSS and CGA-DSS groups received 2.5% DSS in drinking water for 5 days, while the other two groups received sterile water. Compared to DSS alone, CGA was found to reduce the disease activity index, myeloperoxidase activity and tumor necrosis factor-α levels in colon tissues (P < 0.05). CGA also ameliorated DSS-induced inflammatory responses, reduced colon shortening and decreased the histological scores (P < 0.05). In an evaluation of the relative abundances of bacteria in the fecal microbiota, we found that CGA reversed the decrease in diversity caused by DSS and improved the relative abundance of organisms in the genus Lactobacillus (P < 0.05). These results indicate that CGA maintains intestinal health and reduces DSS-induced colon injury by decreasing the production of pro-inflammatory cytokines and restoring intestinal microbial diversity.

Current concepts in pediatric inflammatory bowel disease; IL10/IL10R colitis as a model disease

Inflammatory bowel disease (IBD) is a heterogeneous group of disorders composed mainly of ulcerative colitis (UC) and Crohn's disease (CD) and undetermined IBD. The peak incidence of occurrence is mainly beyond the pediatric age group. Recent knowledge about genetic factors had been strongly linked to pediatric IBD (PIBD). Recent advances in genomic technologies have prompted the identification of genetic defects underlying rare, very early-onset IBD (VEO-IBD) as a disease subgroup noted especially in populations with higher consanguinity rates. A better understanding of key players in the complex homeostasis of the immune system in the gut and illustrating the relationships between intestinal microbiome, systemic immune dysregulation and primary immunodeficiency have received growing recognition over the years. In this article, we provide a review of the key players of the immunity of the gut, compare between adult and pediatric IBD as an interesting module to investigate the relationship between monogenic and multifactorial/polygenic diseases, list genetic mutations confirmed to be linked to VEO IBD and summarize the scientific work that led to the discovery of one of the monogenic mutations related to infantile colitis, namely IL10 and IL10 receptor defects.

An advanced protocol for the purification of whipworm eggs from feces for use as therapeutic agents

Recent studies have attempted to treat autoimmune diseases using Trichuris suis. whipworm) eggs. Large quantities of eggs can be obtained efficiently by collecting from the feces of the porcine hosts rather than by extracting from the female worm uterus. However, it is difficult to process large amounts of feces using the current methods. In the present study, we propose a method to collect the eggs from bulk feces more efficiently. Collecting the eggs using washing meshes (25 μm sieve) yields 65.7% (56.0-70.7) of eggs (median, min-max) from 100 g feces. Our method, which uses ethyl acetate and simulated gastric fluid, yielded 91.4% (91.4-94.0) of the eggs from 100 g feces into the separated aqueous solution. Egg collection using simulated gastric fluid (SGF) method was also 60 min faster than that using the sieve method. As the SGF used in the experiment is a strongly acidic reagent with a pH of 1-2, embryonation of the eggs was induced by the rapid pH change. As a result, 37.1% (8.0-77.8) of the eggs had embryonated two months after SGF stimulation. Using the developed method, we could process the feces quickly and efficiently. Furthermore, after purification, egg embryonation could be induced without any harmful reagent treatment. This method is expected to be helpful for further research using Trichuris suis eggs.

Gastrointestinal Presentations of Common Variable Immunodeficiency: Hiding in Plain Sight

Primary immunodeficiency disorders typically have an onset in childhood. The suspicion for these conditions usually arises from a history of recurrent respiratory, gastrointestinal, or cutaneous infections with a history often dating back to infancy or early childhood. However, adults can also be affected. Common variable immunodeficiency, which usually has an onset/diagnosis in adulthood, is the most common symptomatic primary immunodeficiency. However, as its presentation could be manifold, its diagnosis is often delayed. The gastrointestinal tract is the second most affected system after the respiratory tract; symptoms associated with the gastrointestinal tract are often intractable. As patients with common variable immunodeficiency are often misdiagnosed, a high index of suspicion and clinical correlation is required for the appropriate diagnosis of this potentially debilitating condition.

Checkpoint inhibitor colitis: a new model of inflammatory bowel disease?

PURPOSE OF REVIEW

Immune checkpoint inhibitors are monoclonal antibodies against the inhibitory, co-stimulatory molecules CTLA-4 and PD-1/PD-L1. Their use in oncology has been associated with frequent and diverse immune-related adverse events. In the digestive tract, such toxicity presents primarily as colonic inflammation, resembling inflammatory bowel disease (IBD). This review presents recent developments regarding the characteristics of checkpoint inhibitor colitis (CIC) and its relation to IBD.

RECENT FINDINGS

Several reports from patient cohorts with CIC have outlined its similarities and differences with IBD. Clinically and endoscopically, there is high overlap, including the negative prognostic significance of deep ulceration. Histologically, CIC may present as either acute colitis or demonstrate features of chronic damage, including IBD-like and lymphocytic colitis-like phenotypes. CIC immunopathogenesis appears to be associated with a predominance of mucosal Th1/Th17 effector responses, and may also be influenced by input from the gut microflora. Finally, current treatment of CIC is based on steroids and infliximab, although other biologics such as vedolizumab may also be effective.

SUMMARY

CIC represents a distinct form of colitis with characteristics reminiscent of IBD flares. Clarification of the mechanisms involved in its pathogenesis will greatly enhance our understanding and therapeutic management of immune-mediated colitides, including IBD.

Role of microRNA-223 in the regulation of poly(ADP-ribose) polymerase in pediatric patients with Crohn's disease

OBJECTIVES

Crohn's disease (CD) is a multifactorial disease, characterized by oxidant-induced tissue injury with a possible activation of poly(ADP-ribose) polymerase (PARP)-1. MicroRNAs (miRs) can offer a potential link between the genetic susceptibility, environmental and immunologic factors in the pathogenesis of CD. Previously, PARP-1 was identified as a direct target gene of miR-223 in an epithelial cell line. Our aim was to examine PARP activation and miR-223 expression in colonic biopsies of pediatric CD. To support our in vivo findings, the effect of lipopolysaccharide (LPS) on same parameters was examined in HT-29 colonic epithelial cell line.

METHODS

Colonic biopsies were taken from patients with macroscopically inflamed and intact mucosa with CD and controls. LPS treated HT-29 cells served as our in vitro model. To analyze the PARP-1 expression real-time PCR, Western blot and immunohistochemical analyses were used. PARP-1 enzymatic activity was assessed on the basis of poly(ADP-ribosyl)ated proteins. Expression of miR-223 was examined by real-time PCR.

RESULTS

PARP-1 mRNA and miR-223 expression was significantly elevated, however, the amount of PARP-1 protein and poly(ADP-ribose) was reduced in pediatric CD compared to controls. LPS incubation did not affect the expression of PARP-1 mRNA, however, decreased miR-223 expression, and enhanced PARP-1 activity.

CONCLUSIONS

In our study, we showed that the expression of miR-223 is up-regulated and poly(ADP-ribosyl)ation is reduced in pediatric patients with CD. Moreover, we confirmed their opposite change in LPS treated epithelial cells, too. These data suggest that the hypofunctionality of PARP-1 may play a potential role in the pathomechanism of CD.

Bacille Calmette-Guerin Complications in Newly Described Primary Immunodeficiency Diseases: 2010-2017

Bacille Calmette–Guerin (BCG) vaccine is widely used as a prevention strategy against tuberculosis. BCG is a live vaccine, usually given early in life in most countries. While safe to most recipients, it poses a risk to immunocompromised patients. Several primary immunodeficiency diseases (PIDD) have been classically associated with complications related to BCG vaccine. However, a number of new inborn errors of immunity have been described lately in which little is known about adverse reactions following BCG vaccination. The aim of this review is to summarize the existing data on BCG-related complications in patients diagnosed with PIDD described since 2010. When BCG vaccination status or complications were not specifically addressed in those manuscripts, we directly contacted the corresponding authors for further clarification. We also analyzed data on other mycobacterial infections in these patients. Based on our analysis, around 8% of patients with gain-of-function mutations in STAT1 had mycobacterial infections, including localized complications in 3 and disseminated disease in 4 out of 19 BCG-vaccinated patients. Localized BCG reactions were also frequent in activated PI3Kδ syndrome type 1 (3/10) and type 2 (2/18) vaccinated children. Also, of note, no BCG-related complications have been described in either CTLA4 or LRBA protein-deficient patients; and not enough information on BCG-vaccinated NFKB1 or NFKB2-deficient patients was available to drive any conclusions about these diseases. Despite the high prevalence of environmental mycobacterial infections in GATA2-deficient patients, only one case of BCG reaction has been reported in a patient who developed disseminated disease. In conclusion, BCG complications could be expected in some particular, recently described PIDD and it remains a preventable risk factor for pediatric PIDD patients.

Novel molecular defects associated with very early-onset inflammatory bowel

PURPOSE OF REVIEW

Immune dysregulation disorders present with common clinical features of multiorgan autoimmunity. Gastrointestinal involvement is the hallmark of an impaired immune homeostasis. This review will give an overview on the novel phenotypes, highlighting the major points that will help to enable early diagnosis and treatment.

RECENT FINDINGS

The rapid progress on DNA sequencing technologies have led to the identification of monogenic defects that adversely impact the control of immune homeostasis. Lymphocytes may be present but dysfunctional, allowing for the development of excessive autoreactivity and resultant autoimmune disease. Regulatory T cells (Tregs) play an essential role in enforcing immune tolerance. Here we illustrate disorders caused by impairment of mechanisms ensuring Tregs function (Tregs related) in which autoimmunity is a hallmark of the clinical disease presentation and other disorders, affecting molecules more broadly involved in immune responses and indirectly causing immune dysregulation (Tregs unrelated). Clinical presentation is sometime mischievous and often symptoms are analogous in different diseases and can mislead diagnosis.

SUMMARY

The increasing comprehension of immunological concepts behind immune dysregulation diseases will allow better and in some cases possibly even targeted treatment. A genetic diagnosis therefore becomes important information in this group of patients, especially as some patients might require hematopoietic stem cell transplantation.

Pharmacological treatments and infectious diseases in pediatric inflammatory bowel disease

The incidence of pediatric inflammatory bowel disease (IBD) is rising, as is the employment of immunosuppressive and biological drugs. Most patients with IBD receive immunosuppressive therapies during the course of the disease. These molecules are a double-edged sword; while they can help control disease activity, they also increase the risk of infections. Therefore, it is important that pediatricians involved in primary care, pediatric gastroenterologists, and infectious disease physicians have a thorough knowledge of the infections that can affect patients with IBD. Areas covered: A broad review of the major infectious diseases that have been reported in children and adolescents with IBD was performed, and information regarding surveillance, diagnosis and management were updated. The possible correlations with IBD pharmacological tools are discussed. Expert commentary: Opportunistic infections are possible in pediatric IBD, and immunosuppressive and immunomodulator therapy seems to play a causative role. Heightened awareness and vigilant surveillance leading to prompt diagnosis and treatment are important for optimal management.

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.