Onset Inflammatory Bowel Disease Research Articles

P263 Very early onset Inflammatory Bowel Diseases: Review of the Genoa-Messina joint clinical experience. Clinical history: Part I

Abstract Background Pediatric inflammatory bowel diseases (pIBD) have specific phenotypes compared to Inflammatory Bowel Diseases (IBD) in adults. The Very Early Onset-IBD (VEO-IBD) is considered a diagnosis of IBD in children before age 6 years old with 15% of prevalence. Methods The objective of this study was to compare the clinical and endoscopic features of VEO-IBD compared to pediatric IBD (diagnosis > 6 years old) also in terms of natural history and response to treatment. The VEO patients followed at the IBD-Centers of Messina and Gaslini were enrolled retrospectively. We compared the results of this population with what is reported in the literature in terms of clinical characteristics at onset (symptoms, age at onset, age at diagnosis), comorbidities, complications, associated immunodeficiencies, endoscopic models. Percentage comparison and chi-square test of data was performed. Results 74 VEO-IBD patients were enrolled. The onset is around 3 years, a predominantly colonic localization, inflammatory pattern. Positive family history for IBD in 8.1%. Histology is very nonspecific and is characterized above all by basal plasmacytosis (CD 68,4%; CU 72,7%) and hypereosinophilia (CD 36,8%; CU 40%). At diagnosis, IBD-U (= Unclassified) is prevalent (47,2%), the frequency of which will decrease over the years (3 years after onset, 32.4%), differentiating into CU and CD (table 1). The main clinical manifestations at onset are chronic diarrhea (CD 89,5%; CU 91%), blood in the stool and / or hematochezia (CD 78,9%; CU 96,4%; table 2). Sensitive onset tests for IBD are ESR, fecal calprotectin and iron deficiency anemia (positive respectively in CD 75-60-71,4%%; CU 58,8-84,6-66,7%). The most frequent extraintestinal manifestations are arthritis (CD 22,2%) and sclerosing cholangitis (CU 7,3%). To highlight the significant statistical association (p <0.05) between VEO-IBD and neuro / nephrological diseases (major renal malformations and nephropathies, autism and neuropsychiatric disorders; table 3). Among the most common complications are severe anemia (CD 31,6%; CU 42,6%), acute attack of severe colitis, malnutrition and fistulization. A monogenic form of VEO-IBD was found in 5.4% frequently linked to immunedeficiency, 2 cases required allogenic HSC transplantation (XIAP, WAS). Conclusion VEO-IBDs represent a challenge for the pediatric gastroenterologist. The clinical course is no more severe than pediatric inflammatory bowel diseases, with the exception of monogenic forms. A genetic association between nephro / neurological comorbidities and VEO-IBDs is likely, the genetics is still to be discovered. Further studies will be needed to define the best therapeutic and diagnostic approach for these diseases.

P300 Very early onset Inflammatory Bowel Diseases: Review of the Genoa-Messina joint clinical experience. Therapeutic approach: Part II

Abstract Background Pediatric inflammatory bowel diseases (pIBD) have specific phenotypes compared to Inflammatory Bowel Diseases (IBD) in adults. The Very Early Onset-IBD (VEO-IBD) is considered a diagnosis of IBD in children before age, 6 years old with, 15% of prevalence. Methods The objective of this study was to compare the clinical and endoscopic features of VEO-IBD compared to pediatric IBD (diagnosis >, 6 years old) also in terms of natural history and response to treatment. The VEO patients followed at the IBD-Centers of Messina and Gaslini were enrolled retrospectively. We compared the results of this population with what is reported in the literature in terms of therapeutic approach and surgery. Percentage comparison of data was performed. Results 74 VEO-IBD patients were enrolled. At the onset of the disease, during induction therapy, we found, 15–21% of VEO-IBDs are corticoresistant, remission was with Infliximab (table 1). During disease follow-up of at least, 5 years from onset: CD, 47,4% and CU, 61,1% of VEO-IBDs remain in therapeutic maintenance with, 1st line drugs (Mesalazine and Azathioprine; table 2). This result highlights how the VEO-IBDs also maintain clinical, histological and endoscopic remission even with, 1st line drugs, the only exception being the monogenic forms that may also require HSC transplantation. The surgical approach, according to our data, is far superior to that reported in the literature, although there are several conflicting studies in this regard. Patients undergoing major surgery (colectomy, ileostomy, ileorectoanastomosis, J pouch) are CD, 36.8% and CU, 18.5%, if we also consider minor surgery (perianal surgery; CD, 36.8%) the percentage of patients with Crohn’s disease undergoing surgery increases to, 52.6%. These numbers are far above what is reported in the literature:, 14–15% after, 5 years from diagnosis. It is likely that this result is due to the high numbers of procedures performed at Gaslini Institute, National Center for these diseases. A monogenic form of VEO-IBD was found in, 5.4% frequently linked to immunedeficiency, 2 cases (2,7%) required allogeneic HSC transplantation (XIAP, WAS) with complete recovery from disease. Conclusion VEO-IBDs represent a challenge for the pediatric gastroenterologist. Therapy is no different in terms of response from pediatric inflammatory bowel diseases, with the exception of monogenic forms who may need HSC transplant. Many VEO IBDs maintain remission with, 1st line drugs. Further studies will be needed to define the best therapeutic and diagnostic approach for these diseases.

THE EFFECTS OF HIGH-FAT, LOW-FAT, AND SUCROSE-FREE DIETS ON MICE WITH INNATE IMMUNE MEDIATED COLITIS

While the cause of Inflammatory bowel disease (IBD) is unknown, certain symptoms may be altered by a multitude of factors including genetics, lifestyle choices, and diet choices. High fat diets (HFDs) are diets with fat accounting for ≥20% of total caloric intake. These diets are known risk factors for IBD onset and worsening symptoms.

Adrenomedullin: Not Just Another Gastrointestinal Peptide.

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two bioactive peptides derived from the same precursor with several biological functions including vasodilation, angiogenesis, or anti-inflammation, among others. AM and PAMP are widely expressed throughout the gastrointestinal (GI) tract where they behave as GI hormones, regulating numerous physiological processes such as gastric emptying, gastric acid release, insulin secretion, bowel movements, or intestinal barrier function. Furthermore, it has been recently demonstrated that AM/PAMP have an impact on gut microbiome composition, inhibiting the growth of bacteria related with disease and increasing the number of beneficial bacteria such as Lactobacillus or Bifidobacterium. Due to their wide functions in the GI tract, AM and PAMP are involved in several digestive pathologies such as peptic ulcer, diabetes, colon cancer, or inflammatory bowel disease (IBD). AM is a key protective factor in IBD onset and development, as it regulates cytokine production in the intestinal mucosa, improves vascular and lymphatic regeneration and function and mucosal epithelial repair, and promotes a beneficial gut microbiome composition. AM and PAMP are relevant GI hormones that can be targeted to develop novel therapeutic agents for IBD, other GI disorders, or microbiome-related pathologies.

Food Additives, a Key Environmental Factor in the Development of IBD through Gut Dysbiosis.

Diet is a key environmental factor in inflammatory bowel disease (IBD) and, at the same time, represents one of the most promising therapies for IBD. Our daily diet often contains food additives present in numerous processed foods and even in dietary supplements. Recently, researchers and national authorities have been paying much attention to their toxicity and effects on gut microbiota and health. This review aims to gather the latest data focusing on the potential role of food additives in the pathogenesis of IBDs through gut microbiota modulation. Some artificial emulsifiers and sweeteners can induce the dysbiosis associated with an alteration of the intestinal barrier, an activation of chronic inflammation, and abnormal immune response accelerating the onset of IBD. Even if most of these results are retrieved from in vivo and in vitro studies, many artificial food additives can represent a potential hidden driver of gut chronic inflammation through gut microbiota alterations, especially in a population with IBD predisposition. In this context, pending the confirmation of these results by large human studies, it would be advisable that IBD patients avoid the consumption of processed food containing artificial food additives and follow a personalized nutritional therapy prescribed by a clinical nutritionist.

Twenty-first Century Trends in the Global Epidemiology of Pediatric-Onset Inflammatory Bowel Disease: Systematic Review

The incidence of inflammatory bowel disease (IBD) is increasing internationally, particularly in nations with historically low rates. Previous reports of the epidemiology of pediatric-onset IBD identified a paucity of data. We systematically reviewed the global trends in incidence and prevalence of IBD diagnosed in individuals <21 years old over the first 2 decades of the 21st century. We systematically reviewed studies indexed in MEDLINE, EMBASE, Airiti Library, and SciELO from January 2010 to February 2020 to identify population-based studies reporting the incidence and/or prevalence of IBD, Crohn's disease, ulcerative colitis, and/or IBD-unclassified. Data from studies published before 2000 were derived from a previously published systematic review. We described the geographic distribution and trends in children of all ages and limiting to very early onset (VEO) IBD. A total of 131 studies from 48 countries were included. The incidence and prevalence of pediatric-onset IBD is highest in Northern Europe and North America and lowest in Southern Europe, Asia, and the Middle East. Among studies evaluating trends over time, most (31 of 37, 84%) studies reported significant increases in incidence and all (7 of 7) reported significant increases in prevalence. Data on the incidence and prevalence of VEO-IBD are limited to countries with historically high rates of IBD. Time trends in the incidence of VEO-IBD were visually heterogeneous. Rates of pediatric-onset IBD continue to rise around the world and data are emerging from regions where it was not previously reported; however, there remains a paucity of data on VEO-IBD and on pediatric IBD from developing and recently developed countries.

Cerebrovascular Events in Pediatric Inflammatory Bowel Disease: A Review of Published Cases.

Pediatric inflammatory bowel disease (PIBD) is a multisystem disorder characterized by intestinal and extraintestinal manifestations and complications. Cerebrovascular events (CVE) are rare extraintestinal complications in patients with PIBD. Statistics show that 3.3% patients with PIBD and 1.3–6.4% adult patients with inflammatory bowel disease (IBD) experience CVE during the course of the disease. Therefore, this study aimed to review the records of children with IBD who developed CVE during the course of the disease. We retrospectively reviewed 62 cases of PIBD complicated by CVE. The mean patient age at the time of thrombotic events was 12.48±4.13 years. The incidence of ulcerative colitis was significantly higher than that of Crohn’s disease (43 [70.5%] vs. 13 [21.3%] patients). Most patients (87.93%) were in the active phase of IBD at the time of CVE. The mean time interval between the onset of IBD and CVE was 20.84 weeks. Overall, 11 (26.83%) patients showed neurological symptoms of CVE at disease onset. The most frequent symptom on admission was persistent and severe headaches (67.85%). The most common site of cerebral venous thrombosis was the transverse sinuses (n=23, 53.48%). The right middle cerebral artery (n=3, 33.34%) was the predominant site of cerebral arterial infarction. Overall, 41 (69.49%) patients who were mostly administered unfractionated heparin or low-molecular-weight heparin (56.09%) recovered completely. Patients with IBD are at a risk of thromboembolism. CVE may be the most common type of thromboembolism. Based on these findings, the most common risk factor for CVE is IBD flares. In patients with CVE, anticoagulant therapy with heparin, followed by warfarin, is necessary.

Histopathological Features of Monogenic Inflammatory Bowel Disease: Subanalysis of Systematic Review.

Histopathological Features of Monogenic Inflammatory Bowel Disease: Subanalysis of Systematic Review.

Induction and evaluation of murine colitis induced by T cell transfer.

Inflammatory bowel diseases (IBD) involve repetitive bouts of inflammation in the intestinal tract and can result in severe morbidity for patients. Moreover, long-standing IBD increases the risk for developing intestinal neoplasia. Although several factors including immune cell activity, microbiota and diet have been implicated in IBD pathogenesis, it is still considered a disease of idiopathic origin. Therefore, much work is needed to identify the critical mediators in IBD onset, severity and response to treatment. Mouse models are useful for identifying factors that contribute to IBD and the efficacy of therapy, which can then be tested in humans. There are currently multiple IBD models including the use of chemical induction, genetic manipulation and modulation of the immune response. The T cell transfer colitis model provides a quality mimic of human IBD that is T cell driven and results in inflammation in both the ileum and colon. Here, we have provided a detailed step-by-step protocol to induce inflammation and assess disease severity using this model. Such a detailed methodologic description will help to increase its utilization to advance IBD research.

Matched unrelated donor hematopoietic stem cell transplant as a curative treatment for very early onset inflammatory bowel disease due to interleukin-10 receptor-B defect

Matched unrelated donor hematopoietic stem cell transplant as a curative treatment for very early onset inflammatory bowel disease due to interleukin-10 receptor-B defect

Diagnostic d’une maladie inflammatoire rare et sévère de l’intestin chez un nourrisson présentant des ulcérations péri-orificielles

We report the case of an infant aged 8 and a half months, who had an apparent life-threatening event and died despite optimal resuscitation management. The medical history was marked by mild symptoms, mainly feeding difficulties and progressively settling skin lesions. Parents were related (first cousins) and the patient had two healthy older sisters. Autopsy showed growth delay, symmetrical erythematous and ulcerated periorificial lesions associated with punctiform erythematous lesions of the face and alopecia. Microscopic examination revealed deep bronchial inhalation with the onset of infectious pneumopathy, major inflammatory ulceration of the gastrointestinal tract, hepatic steatosis, brain stem and pancreas abnormalities. We conclude that the cause of death was a multi-visceral failure with inhalation pneumopathy, in a context of very early onset inflammatory bowel disease (VEO-IBD). Genetic consultation, into a rare disease reference center, allowed to orient the analysis, to identify a homozygous pathogenic variant in the IL10RA gene, confirming the diagnostic of an autosomal recessive very early onset inflammatory bowel disease (inflammatory bowel disease 28, early-onset, autosomal recessive, #613148).

Mucins Dynamics in Physiological and Pathological Conditions.

Maintaining intestinal health requires clear segregation between epithelial cells and luminal microbes. The intestinal mucus layer, produced by goblet cells (GCs), is a key element in maintaining the functional protection of the epithelium. The importance of the gut mucus barrier is highlighted in mice lacking Muc2, the major form of secreted mucins. These mice show closer bacterial residence to epithelial cells, develop spontaneous colitis and became moribund when infected with the attaching and effacing pathogen, Citrobacter rodentium. Furthermore, numerous observations have associated GCs and mucus layer dysfunction to the pathogenesis of inflammatory bowel disease (IBD). However, the molecular mechanisms that regulate the physiology of GCs and the mucus layer remain obscured. In this review, we consider novel findings describing divergent functionality and expression profiles of GCs subtypes within intestinal crypts. We also discuss internal (host) and external (diets and bacteria) factors that modulate different aspects of the mucus layer as well as the contribution of an altered mucus barrier to the onset of IBD.

Development of a Personalized Intestinal Fibrosis Model Using Human Intestinal Organoids Derived From Induced Pluripotent Stem Cells.

BackgroundIntestinal fibrosis is a serious complication of Crohn’s disease. Numerous cell types including intestinal epithelial and mesenchymal cells are implicated in this process, yet studies are hampered by the lack of personalized in vitro models. Human intestinal organoids (HIOs) derived from induced pluripotent stem cells (iPSCs) contain these cell types, and our goal was to determine the feasibility of utilizing these to develop a personalized intestinal fibrosis model.MethodsiPSCs from 2 control individuals and 2 very early onset inflammatory bowel disease patients with stricturing complications were obtained and directed to form HIOs. Purified populations of epithelial and mesenchymal cells were derived from HIOs, and both types were treated with the profibrogenic cytokine transforming growth factor β (TGFβ). Quantitative polymerase chain reaction and RNA sequencing analysis were used to assay their responses.ResultsIn iPSC-derived mesenchymal cells, there was a significant increase in the expression of profibrotic genes (Col1a1, Col5a1, and TIMP1) in response to TGFβ. RNA sequencing analysis identified further profibrotic genes and demonstrated differential responses to this cytokine in each of the 4 lines. Increases in profibrotic gene expression (Col1a1, FN, TIMP1) along with genes associated with epithelial-mesenchymal transition (vimentin and N-cadherin) were observed in TGFβ -treated epithelial cells.ConclusionsWe demonstrate the feasibility of utilizing iPSC-HIO technology to model intestinal fibrotic responses in vitro. This now permits the generation of near unlimited quantities of patient-specific cells that could be used to reveal cell- and environmental-specific mechanisms underpinning intestinal fibrosis.

Corticotropin releasing hormone promotes inflammatory bowel disease via inducing intestinal macrophage autophagy

Psychosocial stress is a vital factor contributing to the pathogenesis and progression of inflammatory bowel disease (IBD). The contribution of intestinal macrophage autophagy to the onset and development of IBD has been widely studied. Herein, we investigated the underlying mechanism of psychosocial stress in an IBD mouse model pertaining to macrophage autophagy. Corticotropin releasing hormone (CRH) was peripherally administrated to induce psychosocial stress. For in vivo studies, dextran sulfate sodium (DSS) was used for the creation of our IBD mouse model. For in vitro studies, lipopolysaccharide (LPS) was applied on murine bone marrow-derived macrophages (BMDMs) as a cellular IBD-related challenge. Chloroquine was applied to inhibit autophagy. We found that CRH aggravated the severity of DSS-induced IBD, increasing overall and local inflammatory reactions and infiltration. The levels of autophagy in intestinal macrophages and murine BMDMs were increased under these IBD-related inflammatory challenges and CRH further enhanced these effects. Subsequent administration of chloroquine markedly attenuated the detrimental effects of CRH on IBD severity and inflammatory reactions via inhibition of autophagy. These findings illustrate the effects of peripheral administration of CRH on DSS-induced IBD via the enhancement of intestinal macrophage autophagy, thus providing a novel understanding as well as therapeutic target for the treatment of IBD.

P002 Psychiatric Comorbidity and Suicide in Childhood Onset Immune-Mediated Diseases -A Systematic Review and Meta-Analysis.

The course of paediatric onset immune mediated inflammatory diseases (IMID) is both physically and mentally challenging. Emotional distress with anxiety and depressive symptoms is commonly reported, however, data on diagnosed comorbid psychiatric disorders is scarce. The aim of this study was to provide a literature overview of psychiatric comorbidity, suicide rates, and their potential risk factors, in childhood onset IMID. This was a systematic review following the PRISMA guidelines. The protocol was registered at Prospero (ID: CRD42021233890). A literature search was made in the databases Pubmed, PsychINFO, and Embase. We included the following IMID: paediatric onset inflammatory bowel disease (pIBD), rheumatic diseases (RD) and autoimmune liver diseases. Studies that provided prevalence rates of diagnosed psychiatric disorders and/or suicide, were included. Pooled prevalence rates of psychiatric disorders (grouped according to ICD-10 criteria) reported by three or more studies, within the same IMID, were calculated using random-effects meta-analysis. Two authors independently evaluated risk of bias using the New-Castle Ottawa scale. Twenty-three studies met the inclusion criteria; 13 describing psychiatric disorders in pIBD and 10 in RD. No study reported on psychiatric disorders in autoimmune liver diseases. Compared to controls without somatic disease, IMID patients had an increased risk of psychiatric disorders, with anxiety and mood disorders being the most common. Prevalence rates for anxiety and mood disorders in pIBD were 6% (95% confidence interval (CI): 4%-9%) and 4% (95%CI: 2%-8%), respectively, in register-based studies, and 33% (95%CI: 25%-41%) and 18% (95%CI:12%-26%), respectively, in studies using psychiatric assessment. In RD pooled estimates were 13% (95%CI: 12%-15%) for anxiety disorders and 20% (95%CI: 15%-26%) for mood disorders. Based on single studies, risk of suicide was increased in pIBD, but not in juvenile idiopathic arthritis, the most common RD. In this systematic review, patients with childhood onset IMID had increased prevalence of psychiatric disorders compared to controls. However, only pooled estimates on emotional disorders were possible and studies investigating broad spectrum of psychiatric disorders are needed.

Hematopoietic stem cell transplantation for Inborn Errors of Immunity

Hematopoietic stem cell transplantation for Inborn Errors of Immunity

Roles of Gut Bacteriophages in the Pathogenesis and Treatment of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, are chronic, relapsing intestinal inflammatory disorders. Although the molecular mechanisms governing the pathogenesis of IBD are not completely clear, the main factors are presumed to be a complex interaction between genetic predisposition, host immune response and environmental exposure, especially the intestinal microbiome. Currently, most studies have focused on the role of gut bacteria in the onset and development of IBD, whereas little attention has been paid to the enteroviruses. Among of them, viruses that infect prokaryotes, called bacteriophages (phages) occupy the majority (90%) in population. Moreover, several recent studies have reported the capability of regulating the bacterial population in the gut, and the direct and indirect influence on host immune response. The present review highlights the roles of gut phages in IBD pathogenesis and explores the potentiality of phages as a therapeutic target for IBD treatment.

Long-Term Overconsumption of Fat and Sugar Causes a Partially Reversible Pre-inflammatory Bowel Disease State.

Nutrition appears to be an important environmental factor involved in the onset of inflammatory bowel diseases (IBD) through yet poorly understood biological mechanisms. Most studies focused on fat content in high caloric diets, while refined sugars represent up to 40% of caloric intake within industrialized countries and contribute to the growing epidemics of inflammatory diseases. Herein we aim to better understand the impact of a high-fat-high-sucrose diet on intestinal homeostasis in healthy conditions and the subsequent colitis risk. We investigated the early events and the potential reversibility of high caloric diet-induced damage in mice before experimental colitis. C57BL/6 mice were fed with a high-fat or high-fat high-sucrose or control diet before experimental colitis. In healthy mice, a high-fat high-sucrose diet induces a pre-IBD state characterized by gut microbiota dysbiosis with a total depletion of bacteria belonging to Barnesiella that is associated with subclinical endoscopic lesions. An overall down-regulation of the colonic transcriptome converged with broadly decreased immune cell populations in the mesenteric lymph nodes leading to the inability to respond to tissue injury. Such in-vivo effects on microbiome and transcriptome were partially restored when returning to normal chow. Long-term consumption of diet enriched in sucrose and fat predisposes mice to colitis. This enhanced risk is preceded by gut microbiota dysbiosis and transcriptional reprogramming of colonic genes related to IBD. Importantly, diet-induced transcriptome and microbiome disturbances are partially reversible after switching back to normal chow with persistent sequelae that may contribute to IBD predisposition in the general population.

Association between exposure to air pollutants and the risk of inflammatory bowel diseases visits.

The topic of inflammatory bowel disease (IBD) has attracted more and more attention. Accumulating evidence suggests that exposure to air pollutants is associated with IBD, yet the results are inconsistent and study about daily exposure is few. This study evaluated the association between daily air pollution and IBD in Hefei, China.Daily IBD admission data were obtained from two hospitals in Hefei from January 1, 2019, to December 31, 2019. Daily concentrations of major air pollutants were provided by the Hefei Environmental Protection Bureau. Meteorological data were collected from China Meteorological Data Network. Distributed lag nonlinear model (DLNM) considering both the lag effects of exposure factors and nonlinear relationship of exposure-reaction was used to assess the effect of daily air pollutants exposure on IBD admission.During the study period, totally 886 cases of IBD were recruited, including 313 cases of ulcerative colitis (UC) and 573 cases of Crohn's disease (CD). The findings showed PM2.5, O3, and CO exposure significantly increased the risk of IBD. Mean concentrations of PM2.5, O3, and CO in Hefei were 43.85ug/m3, 100.78ug/m3, and 0.76mg/m3, respectively. Each increase of 10mg/m3 in PM2.5/O3 and 0.1mg/m3 in CO increased the risk of IBD. The strongest effects of these three pollutants on IBD were observed in lag2-lag3 (RR = 1.037, 95% CI: 1.005-1.070%), lag3 (RR = 1.020, 95% CI: 1.002-1.038%), and lag2 (RR = 1.036, 95% CI: 1.003-1.071%), respectively. In warm seasons, PM2.5, O3, and CO had a stronger effect increased the risk of IBD, which were observed in lag2 (RR = 1.104, 95% CI: 1.032-1.181%), lag2 and lag5 (RR = 1.023, 95% CI: 1.002-1.044%; RR = 1.036, 95% CI: 1.004-1.069%), and lag2 (RR = 1.071, 95% CI: 1.012-1.133%), respectively.Air pollutant (PM2.5, O3, and CO) exposure could increase the risk of IBD, while the most susceptibility seasons for the exposure were mainly in warm seasons. The results of this study suggest that air pollutants increase the risk of IBD patients in Hefei, China, providing a basis for developing countries to improve effective prevention of IBD, and a potential opportunity to avoid part of the risk of the onset or recurrence of IBD. This study contributes to the knowledge of the association between air pollution and IBD, but the associations need to be verified by further studies.

Interferon Lambda in the Pathogenesis of Inflammatory Bowel Diseases.

Interferon λ (IFN-λ) is critical for host viral defense at mucosal surfaces and stimulates immunomodulatory signals, acting on epithelial cells and few other cell types due to restricted IFN-λ receptor expression. Epithelial cells of the intestine play a critical role in the pathogenesis of Inflammatory Bowel Disease (IBD), and the related type II interferons (IFN-γ) have been extensively studied in the context of IBD. However, a role for IFN-λ in IBD onset and progression remains unclear. Recent investigations of IFN-λ in IBD are beginning to uncover complex and sometimes opposing actions, including pro-healing roles in colonic epithelial tissues and potentiation of epithelial cell death in the small intestine. Additionally, IFN-λ has been shown to act through non-epithelial cell types, such as neutrophils, to protect against excessive inflammation. In most cases IFN-λ demonstrates an ability to coordinate the host antiviral response without inducing collateral hyperinflammation, suggesting that IFN-λ signaling pathways could be a therapeutic target in IBD. This mini review discusses existing data on the role of IFN-λ in the pathogenesis of inflammatory bowel disease, current gaps in the research, and therapeutic potential of modulating the IFN-λ-stimulated response.