Phenotypic and Genotypic Characterisation of Inflammatory Bowel Disease Presenting Before the Age of 2 years

Infantile and Very Early Onset Inflammatory Bowel Disease: A Multicenter Study

OBJECTIVES

This study described disease characteristics and long-term outcomes in patients diagnosed with very early onset inflammatory bowel disease (VEOIBD) (diagnosed before 6 years of age) and infantile-IBD (before 2 years).

METHODS

Cases from 21 centers worldwide diagnosed with VEOIBD (2008-2018), with minimum 2 years of follow-up, were retrospectively reviewed.

RESULTS

The cohort included 243 patients (52% males, median follow-up of 5.8 [range 2-18] years, including 69 [28%]) with infantile-IBD. IBD subtypes included Crohn's disease (CD), ulcerative colitis (UC), or IBD-unclassified (IBDU) in 30%, 59%, and 11%, respectively. Among patients with CD, 94% had colonic involvement, and among patients with UC/IBDU, 75% had pancolitis. Patients with infantile-IBD presented with higher rates of IBDU, lower hemoglobin and albumin levels, and higher C-reactive protein, and had lower response rates to first-induction therapy and corticosteroids therapy (P < .05 for all). Colectomy and diversion surgeries were performed in 11% and 4%, respectively, with no significant differences between age groups. Corticosteroid-free remission rates were 74% and 78% after 3 and 5 years, respectively, and 86% at end of follow-up. Genetic testing was performed in 96 (40%) patients. Among tested population, 15 (16%) were identified with monogenic disease. This group demonstrated lower response rates to induction therapies, higher rates of surgical intervention, and higher rates of major infections (P < .05 for all).

CONCLUSIONS

Patients with VEOIBD, including infantile-IBD, exhibit low rate of complications and surgical interventions at the long term. Patients with monogenic IBD are at risk for more severe disease course.

Breaking Down Barriers: Epithelial Contributors to Monogenic IBD Pathogenesis

Monogenic causes of inflammatory bowel diseases (IBD) are increasingly being discovered. To date, much attention has been placed in those resulting from inborn errors of immunity. Therapeutic efforts have been largely focused on offering personalized immune modulation or curative bone marrow transplant for patients with IBD and underlying immune disorders. To date, less emphasis has been placed on monogenic causes of IBD that pertain to impairment of the intestinal epithelial barrier. Here, we provide a comprehensive review of monogenic causes of IBD that result in impaired intestinal epithelial barrier that are categorized into 6 important functions: (1) epithelial cell organization, (2) epithelial cell intrinsic functions, (3) epithelial cell apoptosis and necroptosis, (4) complement activation, (5) epithelial cell signaling, and (6) control of RNA degradation products. We illustrate how impairment of any of these categories can result in IBD. This work reviews the current understanding of the genes involved in maintaining the intestinal barrier, the inheritance patterns that result in dysfunction, features of IBD resulting from these disorders, and pertinent translational work in this field.

Genomic testing identifies monogenic causes in patients with very early-onset inflammatory bowel disease: a multicenter survey in an Iranian cohort

Patients with very early-onset inflammatory bowel disease (VEO-IBD) may present because of underlying monogenic inborn errors of immunity (IEI). Strong differences have been observed in the causes of monogenic IBD among ethnic populations. This multicenter study was carried out on 16 Iranian patients with VEO-IBD. We reviewed clinical and basic immunologic evaluation including flow cytometry and immunoglobulin levels. All patients underwent clinical whole exome sequencing (WES). Sixteen patients (8 females and 8 males) with a median age of 43.5 months were enrolled. The median age at the onset of symptoms was 4 months. Most patients (12, 75%) had consanguineous parents. Chronic non-bloody diarrhea (13, 81.3%) and perianal diseases including perianal abscess (6, 37.5%), anal fissure (6, 37.5%), or anal fistula (2, 12.5%) were the most common manifestations. WES identified a spectrum of genetic variants in 13 patients (81.3%): IL10RB (6, 37.5%), MVK (3, 18.8%), and CASP8, SLC35C1, G6PC3, and IKBKB in 1 patient, respectively. In 3 patients (18.7%), no variant was identified. Flow cytometry identified a spectrum of abnormalities that helped to assess the evidence of genetic diagnosis. At the end of the survey, 3 (18.8%) patients were deceased. This high rate of monogenic defects with a broad spectrum of genes reiterates the importance of investigating IEI in patients with infantile-onset IBD.

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.

Long term outcomes in children with trichohepatoenteric syndrome

Trichohepatoenteric syndrome (THES) is a rare autosomal recessive disorder caused by mutations in either TTC37 or SKIV2L, usually leading to congenital diarrhea as part of a multisystem disease. Here, we report on the natural history of the disease for the largest UK cohort of patients with THES from 1996 to 2020. We systematically reviewed the clinical records and pathological specimens of patients diagnosed with THES managed in a single tertiary pediatric gastroenterology unit. Between 1996 and 2020, 13 patients (7 female and 6 male) were diagnosed with THES either by mutation analysis or by clinical phenotype. Two patients died from complications of infection. All patients received parenteral nutrition (PN) of which six patients were weaned off PN. All patients had gastrointestinal tract inflammation on endoscopy. Almost half of the cohort were diagnosed with monogenic inflammatory bowel disease (IBD) by the age of 11 years, confirmed by endoscopic and histological findings. Protracted diarrhea causing intestinal failure improves with time in all patients with THES, but monogenic IBD develops in later childhood that is refractory to conventional IBD treatments. Respiratory issues contribute to significant morbidity and mortality, and good respiratory care is crucial to prevent comorbidity.

A novel biallelic 19-bp deletion in the IL10RB gene caused infant-onset inflammatory bowel disease in a consanguineous family: a molecular docking simulation study and literature review

BACKGROUND

Infantile-onset inflammatory bowel disease (IOIBD) is a gastrointestinal inflammatory condition often associated with monogenic disorders and is frequently caused by Interleukin-10 deficiencies. This study aimed to identify the mutation responsible for IBD in an 8-year-old patient from an Iranian family with consanguineous parents.

METHODS

Whole-exome sequencing (WES) was employed to identify disease-causing variations. Furthermore, we utilized integrated experimental data of HADDOCK molecular docking platform, including NMR spectroscopy, to characterize the mutant protein and elucidate the underlying functional mechanism of the identified mutation's pathogenicity.

RESULTS

Our findings revealed a novel 19-bp deletion mutation (c.25_43del, p.Leu9CysfsTer15) in the IL10RB gene. Sanger sequencing confirmed that this variant was inherited in homozygous state within this family, marking the first mutation identified in exon 1 of this gene. Molecular docking simulation demonstrated that the mutant form of IL10RB exhibited reduced affinity for binding to the Interleukin-10 ligand, leading to disruptions in downstream cellular signaling pathways.

CONCLUSIONS

The identification of this novel genetic variant as a causative factor for IOIBD highlights the clinical value of utilizing genetic testing, such as WES, as a reliable diagnostic approach for patients affected by this condition.

Allogeneic bone marrow transplantation for patients with treatment-refractory Crohn's Disease

Background & aims

Durable remissions of Crohn's Disease (CD) have followed myeloablative conditioning therapy and allogeneic marrow transplantation. For patients with treatment-refractory disease, we used reduced-intensity conditioning to minimize toxicity, marrow from donors with low Polygenic Risk Scores for CD as cell sources, and protracted immune suppression to lower the risk of graft-versus-host disease (GVHD). Our aim was to achieve durable CD remissions while minimizing transplant-related complications.

Methods

DNA from patients and their HLA-matched unrelated donors was genotyped and Polygenic Risk Scores calculated. Donor marrow was infused following non-myeloablative conditioning. Patient symptoms and endoscopic findings were documented at intervals after transplant.

Results

We screened 807 patients, 143 of whom met eligibility criteria; 2 patients received allografts. Patient 1 had multiple complications and died at day 332 from respiratory failure. Patient 2 had resolution of CD symptoms until day 178 when CD recurred, associated with persistent host chimerism in both peripheral blood and intestinal mucosa. Withdrawal of immune suppression was followed by dominant donor immune chimerism in peripheral blood and resolution of CD findings. Over time, mucosal T-cells became donor-dominant. At 5 years after allografting, Patient 2 remained off all medications but had mild symptoms related to a jejunal stricture that required stricturoplasty at 6 years. At 8 years, she remains stable off medications.

Conclusions

The kinetics of immunologic chimerism after allogeneic marrow transplantation for CD patients depends on the intensity of the conditioning regimen and the magnitude of immune suppression. One patient achieved durable improvement of her previously refractory CD only after establishing donor immunologic chimerism in intestinal mucosa. Her course provides proof-of-principal for allografting as a potential treatment for refractory CD, but an immunoablative conditioning regimen should be considered for future studies.(ClinicalTrials.gov, NCT01570348).

Precision medicine in monogenic inflammatory bowel disease: proposed mIBD REPORT standards

Owing to advances in genomics that enable differentiation of molecular aetiologies, patients with monogenic inflammatory bowel disease (mIBD) potentially have access to genotype-guided precision medicine. In this Expert Recommendation, we review the therapeutic research landscape of mIBD, the reported response to therapies, the medication-related risks and systematic bias in reporting. The mIBD field is characterized by the absence of randomized controlled trials and is dominated by retrospective observational data based on case series and case reports. More than 25 off-label therapeutics (including small-molecule inhibitors and biologics) as well as cellular therapies (including haematopoietic stem cell transplantation and gene therapy) have been reported. Heterogeneous reporting of outcomes impedes the generation of robust therapeutic evidence as the basis for clinical decision making in mIBD. We discuss therapeutic goals in mIBD and recommend standardized reporting (mIBD REPORT (monogenic Inflammatory Bowel Disease Report Extended Phenotype and Outcome of Treatments) standards) to stratify patients according to a genetic diagnosis and phenotype, to assess treatment effects and to record safety signals. Implementation of these pragmatic standards should help clinicians to assess the therapy responses of individual patients in clinical practice and improve comparability between observational retrospective studies and controlled prospective trials, supporting future meta-analysis.

Dose escalation of adalimumab as a strategy to overcome anti-drug antibodies: A case report of infantile-onset inflammatory bowel disease

BACKGROUND

Treatment of infantile-onset inflammatory bowel disease (IO-IBD) is often challenging due to its aggressive disease course and failure of standard therapies with a need for biologics. Secondary loss of response is frequently caused by the production of anti-drug antibodies, a well-known problem in IBD patients on biologic treatment. We present a case of IO-IBD treated with therapeutic drug monitoring (TDM)-guided high-dose anti-tumor necrosis factor therapy, in which dose escalation monitoring was used as a strategy to overcome anti-drug antibodies.

CASE SUMMARY

A 5-mo-old boy presented with a history of persistent hematochezia from the 10th d of life, as well as relapsing perianal abscess and growth failure. Hypoalbuminemia, anemia, and elevated inflammatory markers were also present. Endoscopic assessment revealed skip lesions with deep colic ulcerations, inflammatory anal sub-stenosis, and deep fissures with persistent abscess. A diagnosis of IO-IBD Crohn-like was made. The patient was initially treated with oral steroids and fistulotomy. After the perianal abscess healed, adalimumab (ADA) was administered with concomitant gradual tapering of steroids. Clinical and biochemical steroid-free remission was achieved with good trough levels. After 3 mo, antibodies to ADA (ATA) were found with undetectable trough levels; therefore, we optimized the therapy schedule, first administering 10 mg weekly and subsequently up to 20 mg weekly (2.8 mg/kg/dose). After 2 mo of high-dose treatment, ATA disappeared, with concomitant high trough levels and stable clinical and biochemical remission of the disease.

CONCLUSION

TDM-guided high-dose ADA treatment as a monotherapy overcame ATA production. This strategy could be a good alternative to combination therapy, especially in very young patients.

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.

Incidence, Management, and Outcomes of Very Early Onset Inflammatory Bowel Diseases and Infantile-Onset Disease: An Epi-IIRN Study

BACKGROUND & AIMS

In this nationwide study from the Israeli Inflammatory Bowel Disease Research Nucleus, we aimed to describe the incidence of very early onset inflammatory bowel diseases (VEOIBDs) with a focus on infantile-onset disease and to compare management and disease course with older children.

METHODS

Data were retrieved from the 4 Israeli Health Maintenance Organizations covering 98% of the population. Pediatric-onset IBD was categorized as follows: adolescent onset (10 to <18 y), early onset (6 to <10 y), VEOIBD (0 to <6 y), toddler onset (2 to <6 y), and infantile onset (<2 y).

RESULTS

A total of 5243 children with 35,469 person-years of follow-up evaluation, were diagnosed with IBD during 2005 to 2020: 4444 (85%) with adolescent onset, 548 (10%) with early onset, and 251 (4.8%) with VEOIBD, of whom 81 (1.5%) had infantile onset. The incidence of pediatric-onset IBD increased from 10.8 per 100,000 in 2005 to 15.3 per 100,000 in 2019 (average annual percentage change, 2.8%; 95% CI, 2.2%-3.4%), but that of VEOIBD remained stable (average annual percentage change, 0%; 95% CI, -2.5% to 2.6%). The infantile-onset and toddler-onset groups were treated less often with biologics (36% and 35%, respectively) vs the early onset (57%) and adolescent-onset groups (53%; P < .001). The time to steroid dependency was shorter in infantile-onset (hazard ratio [HR], 2.1; 95% CI, 1.5-2.9) and toddler-onset disease (HR, 1.6; 95% CI, 1.2-2.0) vs early onset and adolescent-onset disease, but time to hospitalizations, time to surgery, and growth delay were worse only in infantile-onset disease. In a multivariable model, infantile-onset patients had a higher risk for surgery (HR, 1.4; 95% CI, 1.1-1.9) and hospitalization (HR, 1.7; 95% CI, 1.2-2.4) than the toddler-onset group.

CONCLUSIONS

The incidence of VEOIBD remained stable. Infantile-onset IBD had worse outcomes than older children, while toddler onset had mostly similar outcomes, despite less frequent use of biologics.

Efficacy of short-chain polypeptide-based EEN formulas in alleviating intestinal injury in children with Crohn's disease: a single-center study in China

Short-chain polypeptides are composed of three to nine amino acids, which can be absorbed by the intestinal tract without digestive enzymes and ATP energy. Crohn's disease (CD) is a chronic non-specific disease derived from inflammation and damage of the gastrointestinal tract. In this study, we aim to investigate the effect of short-chain polypeptide-based exclusive enteral nutrition (EEN) formulas on intestinal injury in Chinese children with active CD. From January 2013 to January 2019, a total of 84 consecutive children with a diagnosis of Crohn's disease (CD) in the Department of Pediatric Gastroenterology, Children's Hospital of Nanjing Medical University, were divided into mild and moderate-to-severe active CD groups. Each group was further divided into two subgroups: drug group and short-chain polypeptide plus drug group. Tests were carried out on the levels of intestinal fatty acid binding protein (I-FABP) in the blood, fecal calprotectin (FC), and occludin protein in the intestinal mucosa 1 day before treatment and 8 weeks after treatment. Endoscopic and histopathological observations were detected to compare the changes in intestinal injury in children with active CD. After 8 weeks of treatment, the SES-CD scores and Chiu scores of the ileocecal area and terminal ileum of children with mild active CD and the ileocecal area of children with moderate-to-severe active CD in short-chain polypeptide plus drug group were significantly lower than those in the drug group. The OD value of occludin in the terminal ileum and ileocecal area of children with mild active CD and the ileocecal area of children with moderate-to-severe active CD after short-chain polypeptide-based EEN formulas and drug treatment was significantly higher than those in the drug group (p < 0.05). Meanwhile, the levels of FC and I-FABP were significantly decreased (p < 0.05). The results showed that short-chain polypeptide-based EEN formulas effectively alleviate intestinal injury in children with active CD.

Primary sclerosing cholangitis and overlap features of autoimmune hepatitis: a coming of age or an age-ist problem?

Autoimmune liver diseases are siloed into three syndromes that define clinical practice. These classifiers can, and are, challenged by variant presentations across all ages, something inevitable to disease definitions that rely on interpreting inherently variable semi-quantitative/qualitative clinical, laboratory, pathological or radiological findings. Furthermore this remains premised by an ongoing absence of definable disease aetiologies. Clinicians thus encounter individuals with biochemical, serological, and histological manifestations that are common to both primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH), often labelled as 'PSC/AIH-overlap'. In childhood the term 'autoimmune sclerosing cholangitis (ASC)' may be used, and some propose this to be a distinct disease process. In this article we champion the concept that ASC and PSC/AIH-overlap are not distinct entities. Rather, they represent inflammatory phases of PSC frequently manifesting earlier in disease course, most notably in younger patients. Ultimately, disease outcome remains that of a more classical PSC phenotype observed in later life. Thus, we argue that it is now time to align disease names and descriptions used by clinicians across all patient subpopulations, to help care become uniform and ageless. This will enhance collaborative studies and contribute ultimately to rational treatment advances.

Genomic diagnosis and care co-ordination for monogenic inflammatory bowel disease in children and adults: consensus guideline on behalf of the British Society of Gastroenterology and British Society of Paediatric Gastroenterology, Hepatology and Nutrition

Genomic medicine enables the identification of patients with rare or ultra-rare monogenic forms of inflammatory bowel disease (IBD) and supports clinical decision making. Patients with monogenic IBD frequently experience extremely early onset of treatment-refractory disease, with complex extraintestinal disease typical of immunodeficiency. Since more than 100 monogenic disorders can present with IBD, new genetic disorders and variants are being discovered every year, and as phenotypic expression of the gene defects is variable, adaptive genomic technologies are required. Monogenic IBD has become a key area to establish the concept of precision medicine. Clear guidance and standardised, affordable applications of genomic technologies are needed to implement exome or genome sequencing in clinical practice. This joint British Society of Gastroenterology and British Society of Paediatric Gastroenterology, Hepatology and Nutrition guideline aims to ensure that testing resources are appropriately applied to maximise the benefit to patients on a national scale, minimise health-care disparities in accessing genomic technologies, and optimise resource use. We set out the structural requirements for genomic medicine as part of a multidisciplinary team approach. Initiation of genomic diagnostics should be guided by diagnostic criteria for the individual patient, in particular the age of IBD onset and the patient's history, and potential implications for future therapies. We outline the diagnostic care pathway for paediatric and adult patients. This guideline considers how to handle clinically actionable findings in research studies and the impact of consumer-based genomics for monogenic IBD. This document was developed by multiple stakeholders, including UK paediatric and adult gastroenterology physicians, immunologists, transplant specialists, clinical geneticists, scientists, and research leads of UK genetic programmes, in partnership with patient representatives of several IBD and rare disease charities.

Chromosomal Numerical Aberrations and Rare Copy Number Variation in Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Inflammatory bowel diseases [IBD] have a complex polygenic aetiology. Rare genetic variants can cause monogenic intestinal inflammation. The impact of chromosomal aberrations and large structural abnormalities on IBD susceptibility is not clear. We aimed to comprehensively characterise the phenotype and prevalence of patients with IBD who possess rare numerical and structural chromosomal abnormalities.

METHODS

We performed a systematic literature search of databases PubMed and Embase; and analysed gnomAD, Clinvar, the 100 000 Genomes Project, and DECIPHER databases. Further, we analysed international paediatric IBD cohorts to investigate the role of IL2RA duplications in IBD susceptibility.

RESULTS

A meta-analysis suggests that monosomy X [Turner syndrome] is associated with increased expressivity of IBD that exceeds the population baseline (1.86%, 95% confidence interval [CI] 1.48 to 2.34%) and causes a younger age of IBD onset. There is little evidence that Klinefelter syndrome, Trisomy 21, Trisomy 18, mosaic Trisomy 9 and 16, or partial trisomies contribute to IBD susceptibility. Copy number analysis studies suggest inconsistent results. Monoallelic loss of X-linked or haploinsufficient genes is associated with IBD by hemizygous or heterozygous deletions, respectively. However, haploinsufficient gene deletions are detected in healthy reference populations, suggesting that the expressivity of IBD might be overestimated. One duplication that has previously been identified as potentially contributing to IBD risk involves the IL2RA/IL15R loci. Here we provide additional evidence that a microduplication of this locus may predispose to very-early-onset IBD by identifying a second case in a distinct kindred. However, the penetrance of intestinal inflammation in this genetic aberration is low [<2.6%].

CONCLUSIONS

Turner syndrome is associated with increased susceptibility to intestinal inflammation. Duplication of the IL2RA/IL15R loci may contribute to disease risk.

Development of Very-Early-Onset Inflammatory Bowel Disease After Multiple Early-Life Antibiotic Exposures: A Case Report and Literature Review

The use of antibiotics has increased drastically over the last few decades. Many antibiotics can target the commensal microbiota and promote gut dysbiosis. These alterations contribute to disease onset and exacerbation. Although the etiology of inflammatory bowel disease (IBD) is mostly unknown, it involves a complex interaction among host genetics, microbiota, environmental factors, and aberrant immune responses. Studies have shown a relationship between very-early-onset inflammatory bowel disease (VEO-IBD) and microbiota alterations. The case discussed in this report endorses the current clinical evidence for this interaction. This is an anonymous record review with no identifiers involving a 23-month-old female patient who was brought to the emergency department by her parents due to persistent bloody diarrhea. Eight days before the presentation, she had experienced watery diarrhea that progressed to bloody stools. The patient had a history of acute otitis media, acute enteritis, and right-arm cutaneous abscess, for which she had received multiple antibiotic therapies. Strategies to manipulate the microbiome through diet, probiotics, antibiotics, or fecal microbiota transplantation (FMT) may be used therapeutically to modulate disease activity. A high index of clinical suspicion for VEO-IBD should be maintained for patients with a history of multiple, recurrent antibiotic use. We believe this case report will raise awareness about the issue of early anaerobic antibiotic exposure and help prevent its unnecessary use and, consequently, prevent gut microbiota dysbiosis that can lead to VEO-IBD. Also, our literature review will hopefully prompt clinicians to consider alternative therapeutic options for this patient population, such as rebuilding intestinal microbiota composition to improve VEO-IBD activity.

Infantile-onset inflammatory bowel disease has variable long-term outcomes

Objective and aim

Infantile-onset inflammatory bowel disease (IO-IBD), defined as IBD diagnosed at age 2 years or younger, tends to be more severe and refractory to conventional treatment than IBD diagnosed at a later age. However, data about IO-IBD and its long-term follow up are limited. We thus aimed to evaluate the presentation and long-term outcomes of patients with IO-IBD in a retrospective multicenter study.

Methods

Medical records of patients diagnosed with IO-IBD in eight medical centers during 2000-2017 with at least 1-year follow up were reviewed. Demographics and disease characteristics at diagnosis including age of onset, disease phenotype and location, surgeries, medical therapy, and comorbid conditions were recorded.

Results

Twenty-three patients with IO-IBD (16 males, 70%) were identified and followed for a median (range) of 51.2 (26.0-110.3) months. The mean ages at presentation and at the last follow up were 14 ± 9.8 and 101 ± 77 months, respectively. Six (26%) patients needed ileostomy already at the time of diagnosis and 20 (87%) were treated with corticosteroids. During long-term follow up, remission was achieved in 16 (73%) patients; of whom, 3 (14%) were without medications and 7 (32%) were in remission with the use of 5-aminosalicylic acid only. One patient needed hemicolectomy and one developed a severe EBV related infection.

Conclusion

The majority of patients with IO-IBD achieved long-term remission, despite a severe disease presentation at diagnosis. Surgery rate however is high, mainly during the first months from diagnosis.

Understanding inborn errors of immunity: A lens into the pathophysiology of monogenic inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions of the gastrointestinal tract, including Crohn’s disease, ulcerative colitis and inflammatory bowel disease-undefined (IBD-U). IBD are understood to be multifactorial, involving genetic, immune, microbial and environmental factors. Advances in next generation sequencing facilitated the growing identification of over 80 monogenic causes of IBD, many of which overlap with Inborn errors of immunity (IEI); Approximately a third of currently identified IEI result in gastrointestinal manifestations, many of which are inflammatory in nature, such as IBD. Indeed, the gastrointestinal tract represents an opportune system to study IEI as it consists of the largest mass of lymphoid tissue in the body and employs a thin layer of intestinal epithelial cells as the critical barrier between the intestinal lumen and the host. In this mini-review, a selection of pertinent IEI resulting in monogenic IBD is described involving disorders in the intestinal epithelial barrier, phagocytosis, T and B cell defects, as well as those impairing central and peripheral tolerance. The contribution of disrupted gut-microbiota-host interactions in disturbing intestinal homeostasis among patients with intestinal disease is also discussed. The molecular mechanisms driving pathogenesis are reviewed along with the personalized therapeutic interventions and investigational avenues this growing knowledge has enabled.

Utilization of Antitumor Necrosis Factor Biologics in Very Early Onset Inflammatory Bowel Disease: A Multicenter Retrospective Cohort Study From North America

BACKGROUND

Research on the utilization and effectiveness of antitumor necrosis factor (TNF) biologics in children with very early onset inflammatory bowel disease (VEOIBD) is urgently needed. Here we describe anti-TNF use and durability in a multicenter cohort.

METHODS

We performed a retrospective cohort study of patients diagnosed with VEOIBD (<6 years) between 2008 and 2013 at 25 North American centers. We performed chart abstraction at diagnosis and 1, 3, and 5 years after diagnosis. We examined the rate of initiation and durability of infliximab and adalimumab and evaluated associations between treatment durability and the following covariates with multivariate Cox proportional hazard regression: age at diagnosis, sex, disease duration, disease classification, and presence of combined immunomodulatory treatment versus monotherapy.

RESULTS

Of 294 children with VEOIBD, 120 initiated treatment with anti-TNF therapy and 101 had follow-up data recorded [50% Crohn disease (CD), 31% ulcerative colitis (UC), and 19% IBD unclassified (IBD-U)]. The cumulative probability of anti-TNF treatment was 15% at 1 year, 30% at 3 years, and 45% at 5 years from diagnosis; 56 (55%) were treated between 0 and 6 years old. Anti-TNF durability was 90% at 1 year, 75% at 3 years, and 55% at 5 years. The most common reason for discontinuation of anti-TNF were loss of response in 24 (57%) children. Children with UC/IBD-U had lower durability than those with CD (hazard ratio [HR] 0.17; 95% confidence interval [CI], 0.06-0.51; P = 0.001).

CONCLUSIONS

Utilization and durability of anti-TNF in VEOIBD is relatively high and comparable with older children. Having Crohn disease (compared with UC/IBD-U) is associated with greater durability.

Clinical outcome of infantile-onset inflammatory bowel disease in 102 patients with interleukin-10 signalling deficiency

BACKGROUND

Infantile-onset inflammatory bowel disease can be caused by defects in interleukin-10 signalling. The natural history and clinical outcomes of allogeneic haematopoietic stem cell transplantation, medical treatment and surgery have not been thoroughly described.

AIMS

This study evaluates disease progression and clinical outcome in patients with interleukin-10 signalling deficiency.

METHODS

One hundred and nine patients with interleukin-10 signalling deficiency were retrospectively reviewed from a single tertiary centre. The Kaplan-Meier method was applied to calculate probabilities of survival and interval between transplant and stoma closure.

RESULTS

One hundred and nine patients were reviewed, and 102 patients were included in the survival analysis. One hundred and eight patients were identified with IL10RA mutations, and one patient harboured IL10RB mutation. Seventy-three patients received haematopoietic stem cell transplantation. The overall survival after transplantation was 64.2% (95% confidence interval, 52.8 to 75.6), and without transplantation, it was 47.5% (95% confidence interval, 14.8 to 80.2, P = 0.47). The median timeframe between transplant and stoma closure was 19.6 months. The probability of survival was significantly lower in patients with perforation (P < 0.001), ileus (P = 0.038) and without thalidomide treatment (P < 0.001) among patients who did not receive haematopoietic stem cell transplantation. The survival probability was not associated with timeframe between transplant and onset, graft source and genotypes.

CONCLUSIONS

The survival probability was not significantly different between patients with transplantation and the non-transplanted patients.

Clinical Spectrum of Monogenic Infantile-Onset Inflammatory Bowel Disease

Very-early-onset IBD and infantile-onset IBD is extremely rare in children. There is paucity of data with regards to clinical profile and outcome of children with infantile-onset IBD from India. The clinicolaboratory profile, molecular genetic testing and treatment details of 8 children diagnosed with monogenic infantile-onset IBD during 2015-2020 is described here. The median age at onset of symptoms was 3 mo. Sibling death and consanguinity were noted in 4 (50%) each respectively. Diarrhea was the presentation in all (100%) and hematochezia in 5 (62%). Colonic ulcers on colonosopy was seen in 7 infants. The common mutation identified was IL-10R gene in 3 (42%) and LRBA gene mutation in 2 (25%). HSCT was done in 4 children and the rest were managed conservatively. Although there was no mortality in this series, two children (25%) were lost for follow-up.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

EpCAM Is Essential to Maintaining the Immune Homeostasis of Intestines via Keeping the Expression of pIgR in the Intestinal Epithelium of Mice

EpCAM deficiency causes congenital tufting enteropathy (CTE) which is considered as one kinds of very early onset inflammatory bowel disease (IBD). However, functions of EpCAM on regulating the immunity of intestines are still unclear. To study the mechanism of EpCAM on maintaining the intestinal immune homeostasis, the intestines of WT and EpCAM^-/- mice at E18.5, P0 and P3 stages were collected for morphological, histological and gene expression tests. Serious inflammation was detected in the small intestines of P3 EpCAM^-/- mice. Compared to WT mice, genes related to inflammatory factors and immunity cells, including TNFα, IL-1β, IL-6, IL-8rb, MIP2, MCP1, Ly6d and Ly6g, were all significantly upregulated and the expression of intestinal abundance matrix metalloproteinases (MMPs) was also significantly increased in the intestines of EpCAM^-/- mice at E18.5, P0 and P3 stages. Signals of p38, ERK1/2 and JNK were hyper-activated in the intestines of EpCAM^-/- mice. The expression of pIgR was significantly decreased and the expression and activation of transcriptional factors which promote the expression of pIgR were also reduced in the intestines of EpCAM^-/- mice compared to WT controls. In conclusion, EpCAM could maintain the immune homeostasis of intestines via keeping the expression of pIgR in the intestinal epithelium.

Clinical Phenotypes and Outcomes in Monogenic Versus Non-monogenic Very Early Onset Inflammatory Bowel Disease

BACKGROUND AND AIMS

Over 80 monogenic causes of very early onset inflammatory bowel disease [VEOIBD] have been identified. Prior reports of the natural history of VEOIBD have not considered monogenic disease status. The objective of this study is to describe clinical phenotypes and outcomes in a large single-centre cohort of patients with VEOIBD and universal access to whole exome sequencing [WES].

METHODS

Patients receiving IBD care at a single centre were prospectively enrolled in a longitudinal data repository starting in 2012. WES was offered with enrollment. Enrolled patients were filtered by age of diagnosis <6 years to comprise a VEOIBD cohort. Monogenic disease was identified by filtering proband variants for rare, loss-of-function, or missense variants in known VEOIBD genes inherited according to standard Mendelian inheritance patterns.

RESULTS

This analysis included 216 VEOIBD patients, followed for a median of 5.8 years. Seventeen patients [7.9%] had monogenic disease. Patients with monogenic IBD were younger at diagnosis and were more likely to have Crohn's disease phenotype with higher rates of stricturing and penetrating disease and extraintestinal manifestations. Patients with monogenic disease were also more likely to experience outcomes of intensive care unit [ICU] hospitalisation, gastrostomy tube, total parenteral nutrition use, stunting at 3-year follow-up, haematopoietic stem cell transplant, and death. A total of 41 patients [19.0%] had infantile-onset disease. After controlling for monogenic disease, patients with infantile-onset IBD did not have increased risk for most severity outcomes.

CONCLUSIONS

Monogenic disease is an important driver of disease severity in VEOIBD. WES is a valuable tool in prognostication and management of VEOIBD.

[Chronic or severe enteropathy and immunodeficiency: be prepared for a rara avis]

In the work-up of chronic enteropathies an underlying inborn error of immunity (IEI) should be considered in certain cases. IEI are rare, but approximately 10% of patients may present with symptoms of inflammatory bowel disease (IBD), which is a much more common entity. Patients with IEI associated IBD may show extraintestinal symptoms or signs, and are often refractory to conventional anti-inflammatory treatment. In case of early-onset bowel inflammation and other intestinal or extraintestinal manifestations, an IEI should be excluded. A small fraction of monogenic IEI can be amenable to targeted therapies, or even corrected by allogeneic stem cell transplantation. Therefore, early diagnosis is crucial. This paper shows examples of clinical - gastrointestinal as well as extraintestinal - signs and findings which require immunological and possibly genetic workup.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pattern-based Histologic Approach in Very Early Onset IBD: Main Features and Differential Diagnosis

Very early onset inflammatory bowel disease (VEO-IBD) is a clinical umbrella classification composed of IBD-like diseases encompassing both classic IBD (Crohn's disease and ulcerative colitis) and monogenic disorder, both arising before 6 years of age. VEO-IBD patients present significant clinical differences from IBD occurring in older children and in adults, including more severe disease, often unresponsive to conventional IBD therapy and a greater proportion of cases featuring an underlying genetic alteration. Histologic findings of gastrointestinal biopsies can show an IBD-like pattern (both Crohn's disease-like and ulcerative colitis-like pattern), an apoptotic-like and enterocolitis-like pattern. Findings of specific morphologic alterations, such as villous blunting, apoptosis, dense eosinophilic infiltrates, lack of plasma cells and severe glandular atrophy, can suggest a monogenic disorder. Moreover, individuals with monogenic disorders may develop significant problems such as primary immunodeficiency, impacting treatment options. Finally, IBD histology in childhood can differ from that in older patients and adults. This complexity makes a differential diagnosis between IBD and other pediatric diseases involving the gastrointestinal tract difficult, especially considering that histologic features can be similar between different diseases. Without an appropriate diagnosis, the clinical course of VEO-IBD has greater potential for escalated treatment regimens involving extensive surgery and more intensive medical therapies rather than specific therapy directed toward the underlying defect. For these reasons, a pattern-based histologic approach correlated with clinical and laboratory findings with a multidisciplinary approach is fundamental to reach a correct diagnosis in an adequate clinical context.

A Pattern-based Pathology Approach to Very Early-onset Inflammatory Bowel Disease: Thinking Beyond Crohn Disease and Ulcerative Colitis

Very early-onset inflammatory bowel disease (VEO-IBD), IBD diagnosed in children younger than 6 years old, is phenotypically and genetically distinct from older onset IBD. Monogenic and digenic causative defects, particularly in primary immunodeficiency and intestinal epithelial barrier genes, have been identified in a subset of patients with VEO-IBD allowing for targeted therapies and improved outcomes. However, these findings are the minority, thus strategies to correctly diagnose patients, including identification of specific histopathologic findings with correlating clinical and laboratory features may provide critical and necessary insight into mechanisms of disease pathogenesis and subsequent therapeutic options. In this article, we review the pathologic findings seen in patients with VEO-IBD and outline a pattern-based approach to diagnosis using examples from primary immunodeficiencies with gastrointestinal manifestations.

A Rare Cause of Rectovaginal Fistula in Early Infancy: It is in the Genes!

Acquired Rectovaginal Fistula (RVF) is rare in infants. Interleukin10/ Interleukin 10 receptor deficiencies are monogenic disorders presenting as aggressive forms of infantile onset inflammatory bowel disease with perianal abscess and fistula. Genetic studies assist in confirming the diagnosis. We present a two month old infant with rectovaginal fistula, severe colitis, failure to thrive and recurrent infections in whom colonoscopy revealed irregular colonic ulcers, and genetic studies confirmed an IL10RB mutation. Hematopoietic Stem cell transplantation is the definitive therapy for this disorder which the child underwent. We report this infant with an acquired RVF with extraintestinal features due to IL10RB mutation to highlight the importance of thinking beyond the local anatomy and looking into the genetic domain.

Very early onset inflammatory bowel disease in a South Asian country where inflammatory bowel disease is emerging: a distinct clinical phenotype from later onset disease

BACKGROUND/AIMS

Information on pediatric inflammatory bowel disease (PIBD) and very early onset IBD (VEOIBD) are sparse in India, where IBD is emerging. We aimed to evaluate characteristics of VEOIBD and later onset PIBD (LO-PIBD) in India.

METHODS

We performed retrospective analysis of a large, prospectively maintained IBD registry. PIBD was divided in to VEOIBD ( < 6 years) and LO-PIBD (6-17 years). Demographic data, disease characteristics and treatment were compared between the PIBD groups and with other Asian/Western studies as well as the adult patients of the registry.

RESULTS

Of 3,752 IBD patients, 292 (7.8%) had PIBD (0-17 years) (175 Crohn's disease [CD], 113 ulcerative colitis [UC], 4 IBD-undifferentiated; 22 VEOIBD [7.5%], and 270 LO-PIBD [92.5%]). VEOIBD patients had more severe disease compared to LO-PIBD in both UC (P= 0.003) and CD (P< 0.001). Familial IBD was more common in VEOIBD (13.6%) compared to LO-PIBD (9.2%). Ileal disease (L1) was an independent risk factor for diagnostic delay in pediatric CD. Diagnostic delay ( > 6 months) was significantly lower in VEOIBD (40.9%) than in LO-PIBD (78.8%) (P< 0.001). Compared to other Asian and Western studies, extensive UC (72.5%) and complicated CD (stricturing/penetrating: 42.7%) were relatively more common. Perianal CD was relatively less frequent (7.4%). PIBD had a significantly higher number of complicated and ileal CD and extensive UC comparison to adult cohort of the registry.

CONCLUSIONS

VEOIBD has more aggressive phenotype than LO-PIBD. Disease appears distinct from other Asian and Western studies and adult onset disease, with more complicated CD and extensive UC.

A Multicenter Prospective Survey on Early-Onset Inflammatory Bowel Disease in Japan

INTRODUCTION

The incidence of early-onset inflammatory bowel disease is increasing in Japan.

OBJECTIVE

This study aimed to analyze the treatment and progress of early-onset inflammatory bowel disease.

METHODS

This prospective survey evaluated the data of 43 patients aged <8 years who were diagnosed with inflammatory bowel disease (IBD) from the time of diagnosis to 36 months after registration.

RESULTS

A total of 12 patients with Crohn's disease (CD), 21 with ulcerative colitis (UC), and 3 with unclassified IBD were enrolled. The mean disease onset age was 3 years and 7 months. Colon and anal lesions were present in 100 and 50% of patients with CD, respectively. Granulomas were detected in 5 patients (41.7%). Dietary elimination including elemental diet was performed in all patients. Eleven patients (91.7%) were in remission by initial induction therapy, and 72.7% maintained remission for 36 months. Three patients (14.3%) with UC had familial history, 71.4% had pancolitis-type UC, and 66.7% exhibited disease of moderate severity. Colectomy was performed in 4 patients (21.1%). Eighteen patients (85.7%) were in remission by initial induction therapy; however, only 15.8% maintained remission for 36 months. Anal complication was more prevalent in infantile-onset IBD than in childhood-onset IBD (p = 0.014).

CONCLUSIONS

Among Japanese patients aged <8 years who were diagnosed with IBD, colitis-type disease was more common in CD and pancolitis was more common in UC. As the courses of several patients were severe, identifying primary immunodeficiency appears to be necessary to confirm background disease.

Interleukin 10 and interleukin 10 receptor in paediatric inflammatory bowel disease: from bench to bedside lesson

Background

The differences between adults and children in inflammatory bowel disease (IBD) phenotype, severity, complications, co-morbidities, and response to the therapy resulted in the extraction of paediatric IBD. It has been revealed that the substantial role in the development of IBD in children under 6 years of age plays a single genetic mutation (monogenic IBD). On the other hand, in older children and adolescents IBD is usually associated with number of interactions between susceptibility loci (polygenic IBD).

Main body

Until now there have been described about 60 monogenic defects which affect the variety of immune mechanisms in IBD pathogenesis including epithelial barrier, function of neutrophil granulocytes and phagocytes, T- and B-cell selection and activation, immune inhibitory mechanisms, or apoptosis. Il-10 is an anti-inflammatory cytokine which modulates innate and adaptive immunity affecting expression of pro-inflammatory molecules and function of the variety of immune cells. Patients with identified defects in Il-10 pathway manifest with life-threating colitis with perianal lesions which occurs within first months of life. Allogenic hematopoietic stem cell transplantation is curative therapy in children with Il-10 signalling defects.

Conclusion

Clinical awareness of Il-10 signalling defects enables early recognition and prompt management of the disease.

Mutation spectrum of NOD2 reveals recessive inheritance as a main driver of Early Onset Crohn's Disease

Inflammatory bowel disease (IBD), clinically defined as Crohn’s disease (CD), ulcerative colitis (UC), or IBD-unclassified, results in chronic inflammation of the gastrointestinal tract in genetically susceptible hosts. Pediatric onset IBD represents ≥ 25% of all IBD diagnoses and often presents with intestinal stricturing, perianal disease, and failed response to conventional treatments. NOD2 was the first and is the most replicated locus associated with adult IBD, to date. However, its role in pediatric onset IBD is not well understood. We performed whole-exome sequencing on a cohort of 1,183 patients with pediatric onset IBD (ages 0–18.5 years). We identified 92 probands with biallelic rare and low frequency NOD2 variants accounting for approximately 8% of our cohort, suggesting a Mendelian inheritance pattern of disease. Additionally, we investigated the contribution of recessive inheritance of NOD2 alleles in adult IBD patients from a large clinical population cohort. We found that recessive inheritance of NOD2 variants explains ~ 7% of cases in this adult IBD cohort, including ~ 10% of CD cases, confirming the observations from our pediatric IBD cohort. Exploration of EHR data showed that several of these adult IBD patients obtained their initial IBD diagnosis before 18 years of age, consistent with early onset disease. While it has been previously reported that carriers of more than one NOD2 risk alleles have increased susceptibility to Crohn’s Disease (CD), our data formally demonstrate that recessive inheritance of NOD2 alleles is a mechanistic driver of early onset IBD, specifically CD, likely due to loss of NOD2 protein function. Collectively, our findings show that recessive inheritance of rare and low frequency deleterious NOD2 variants account for 7–10% of CD cases and implicate NOD2 as a Mendelian disease gene for early onset Crohn’s Disease.

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.

Etiology and Management of Pediatric Intestinal Failure: Focus on the Non-Digestive Causes

Background: Intestinal failure (IF) is defined as reduction in functioning gut mass below the minimal amount necessary for adequate digestion and absorption. In most cases, IF results from intrinsic diseases of the gastrointestinal tract (digestive IF) (DIF); few cases arise from digestive vascular components, gut annexed (liver and pancreas) and extra-digestive organs or from systemic diseases (non-digestive IF) (NDIF). The present review revised etiology and treatments of DIF and NDIF, with special focus on the pathophysiological mechanisms, whereby NDIF develops. Methods: We performed a comprehensive search of published literature from January 2010 to the present by selecting the following search strings: “intestinal failure” OR “home parenteral nutrition” OR “short bowel syndrome” OR “chronic pseudo-obstruction” OR “chronic intestinal pseudo-obstruction” OR “autoimmune enteropathy” OR “long-term parenteral nutrition”. Results: We collected overall 1656 patients with well-documented etiology of IF: 1419 with DIF (86%) and 237 with NDIF (14%), 55% males and 45% females. Among DIF cases, 66% had SBS and among NDIF cases 90% had malabsorption/maldigestion. Conclusions: The improved availability of diagnostic and therapeutic tools has increased prevalence and life expectancy of rare and severe diseases responsible for IF. The present review greatly expands the spectrum of knowledge on the pathophysiological mechanisms through which the diseases not strictly affecting the intestine can cause IF. In view of the rarity of the majority of pediatric IF diseases, the development of IF Registries is strongly required; in fact, through information flow within the network, the Registries could improve IF knowledge and management.

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.

Clinical Features and Outcomes of Very-Early-Onset Inflammatory Bowel Disease in Brazilian Children

We report on 20 Brazilian children under 6 years of age with very-early-onset inflammatory bowel disease naive to treatment. The clinical, laboratory, and histopathologic findings at diagnosis and outcomes were reviewed: 13 had ulcerative colitis (UC) and 7 had Crohn disease (CD). The final diagnostic pattern was as follows: 4 children had neonatal-onset (1 UC and 3 CD), 8 had infantile subtype (4 UC and 4 CD), and 8 had UC beyond the neonatal and infantile period. Both forms of inflammatory bowel disease were severe and extensive at diagnosis, with a high prevalence of bloody diarrhea, reflecting the colonic location of the disease. UC was predominantly pancolonic, CD was isolated in the colon and associated with perianal disease. Children with CD were younger than those with UC, were significantly more nutritionally impaired, and had more complications. This study shows that very-early-onset inflammatory bowel disease has an aggressive clinical course with 2 distinct phenotypes, UC and CD, with differences in severity, clinical behavior, and inflammatory pattern but with a preponderance of colonic involvement in both types.

Valuable clinical indicators for identifying infantile-onset inflammatory bowel disease patients with monogenic diseases

BACKGROUND

Infantile-onset inflammatory bowel disease (IO-IBD) occurs in very young children and causes severe clinical manifestations, which has poor responses to traditional inflammatory bowel disease (IBD) treatments. At present, there are no simple and reliable laboratory indicators for early screening IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.

AIM

To search for valuable indicators for early identifying IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.

METHODS

A retrospective analysis was performed in 73 patients with IO-IBD admitted to our hospital in the past 5 years. Based on the next-generation sequencing results, they were divided into a monogenic IBD group (M-IBD) and a non-monogenic IBD group (NM-IBD). Forty age-matched patients with allergic proctocolitis (AP) were included in a control group. The clinical manifestations and the inflammatory factors in peripheral blood were evaluated. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were used to identify the screening factors and cut-off values of IO-IBD as well as monogenic IO-IBD, respectively.

RESULTS

Among the 44 M-IBD patients, 35 carried IL-10RA mutations, and the most common mutations were c.301C>T (p.R101W, 30/70) and the c.537G>A (p.T179T, 17/70). Patients with higher serum tumor necrosis factor (TNF)-α value were more likely to have IBD [odds ratio (OR) = 1.25, 95% confidence interval (CI): 1.05-1.50, P = 0.013], while higher serum albumin level was associated with lower risk of IBD (OR = 0.86, 95%CI: 0.74-1.00, P = 0.048). The cut-off values of TNF-α and albumin were 17.40 pg/mL (sensitivity: 0.78; specificity: 0.88) and 36.50 g/L (sensitivity: 0.80; specificity: 0.90), respectively. The increased ferritin level was indicative of a genetic mutation in IO-IBD patients. Its cut-off value was 28.20 ng/mL (sensitivity: 0.93; specificity: 0.92). When interleukin (IL)-10 level was higher than 33.05 pg/mL (sensitivity: 1.00; specificity: 0.84), or the onset age was earlier than 0.21 mo (sensitivity: 0.82; specificity: 0.94), the presence of disease-causing mutations in IL-10RA in IO-IBD patients was strongly suggested.

CONCLUSION

Serum TNF-α and albumin level could differentiate IO-IBD patients from allergic proctocolitis patients, and serum ferritin and IL-10 levels are useful indicators for early diagnosing monogenic IO-IBD.

Very early-onset inflammatory bowel disease in Japan: A nationwide survey

BACKGROUND AND AIM

Very early-onset inflammatory bowel disease is defined as inflammatory bowel disease diagnosed before 6 years of age. Very early-onset inflammatory bowel disease has various differential diagnoses, including primary immunodeficiency disorders, and is known to be resistant to conventional treatment. Therefore, global attention is required to manage this challenging condition. We conducted a retrospective epidemiological survey of the number of patients, final diagnosis, and examinations performed to diagnose very early-onset inflammatory bowel disease in Japan.

METHODS

A primary questionnaire about the number of very early-onset bowel disease cases and its diagnosis was administered to 630 pediatric facilities nationwide in Japan. A secondary survey about the examinations performed to achieve diagnosis was sent to the facilities that responded to the first survey.

RESULTS

The answering rate was 92.2% (581/630 facilities); 81 facilities had 225 very early-onset bowel disease patients undergoing their care during the past 68 months. Twenty-six patients (11.6%) were diagnosed with immunodeficiency-associated inflammatory bowel disease. The answering rate of the secondary survey was 70.4% (57/81 facilities). Colonoscopy, esophagogastroduodenoscopy, and small bowel imaging were performed for 99.4%, 67.5%, and 28.8% of patients, respectively. Genetic analysis was performed for 26.9% (43/160 patients) of patients, and 51.2% (22/43) of patients were diagnosed with immunodeficiency-associated inflammatory bowel disease.

CONCLUSIONS

Approximately 40 patients are diagnosed yearly in Japan. Imaging studies, especially for small bowel lesions, can be challenging for this unique group of patients. However, a comprehensive approach including immunological and genetic analyses appears useful for diagnosing immunodeficiency-associated inflammatory bowel disease.

Advances in Therapeutic Drug Monitoring in Biologic Therapies for Pediatric Inflammatory Bowel Disease

In the current era of treat-to-target strategies, therapeutic drug monitoring (TDM) has emerged as a potential tool in optimizing the efficacy of biologics for children diagnosed with inflammatory bowel disease (IBD). The incorporation of TDM into treatment algorithms, however, has proven to be complex. "Proactive" TDM is emerging as a therapeutic strategy due to a recently published pediatric RCT showing a clear benefit of "proactive" TDM in anti-TNF therapy. However, target therapeutic values for different biologics for different disease states [ulcerative colitis (UC) vs. Crohn's disease (CD)] and different periods of disease activity (induction vs. remission) require further definition. This is especially true in pediatrics where the therapeutic armamentarium is limited, and fixed weight-based dosing may predispose to increased clearance leading to decreased drug exposure and subsequent loss of response (pharmacokinetic and/or immunogenic). Model-based dosing for biologics offers an exciting insight into dose individualization thereby minimizing the chances of losing response. Similarly, point-of-care testing promises real-time assessment of drug levels and individualized decision-making. In the current clinical realm, TDM is being used to prolong drug durability and efficacy and prevent loss of response. Ongoing innovations may transform it into a personalized tool to achieve optimal therapeutic endpoints.

MHC Class III RNA Binding Proteins and Immunity

Here we review data suggestive of a role for RNA-binding proteins in vertebrate immunity. We focus on the products of genes found in the class III region of the Major Histocompatibility Complex. Six of these genes, DDX39B (aka BAT1), DXO, LSM2, NELFE, PRRC2A (aka BAT2), and SKIV2L, encode RNA-binding proteins with clear roles in post-transcriptional gene regulation and RNA surveillance. These genes are likely to have important functions in immunity and are associated with autoimmune diseases.

Evaluation of very early-onset inflammatory bowel disease

PURPOSE OF REVIEW

Very early-onset inflammatory bowel disease (VEO-IBD) is a rare presentation defined as onset of intestinal inflammation at the age of <6 years. Some of these young children develop IBD because of inherent defects in immune or epithelial cell function resulting from deleterious mutations in genes involved in mucosal homeostasis. Here, we provide an overview of the clinical, genetic and immunologic approach in patients with VEO-IBD.

RECENT FINDINGS

More than 50 different monogenic disorders directly causing IBD have been identified in the last decade; most of them present with unique clinical features in the first years of life. Such a diagnosis may facilitate the administration of targeted therapies and is important for genetic counseling. Nevertheless, a monogenic disorder is identified only in a minority of patients with VEO-IBD. Consequently, different demographic, clinical and histologic features should prompt a detailed genetic and immunologic workup in patients with IBD.

SUMMARY

A diagnosis of monogenic IBD can have a huge impact on patient's care, enabling in some cases to provide personalized therapies. Clinicians should be aware of unique features of such disorders, and complete a detailed genetic and immune workup in selected cases, even when disease manifests beyond a young age.

Paediatric inflammatory bowel disease in India: a prospective multicentre study

BACKGROUND

Paediatric inflammatory bowel disease (PIBD) is increasing across the world. However, information from India is sparse. This multicentre study evaluated the demographics, clinical phenotype and outcome of PIBD from India.

METHODS

Data of children (≤18 years) with PIBD were collected using a proforma containing details of demographics, clinical profile, extraintestinal manifestations (EIM), investigations, disease extent and treatment.

RESULTS

Three hundred twenty-five children [Crohn's disease: 65.2%, ulcerative colitis: 28.0%, IBD unclassified (IBDU): 6.7%, median age at diagnosis: 11 (interquartile range 6.3) years] were enrolled. 6.9% children had family history of IBD. Pancolitis (E4) was predominant in ulcerative colitis (57.8%) and ileocolonic (L3, 55.7%) in Crohn's disease. Perianal disease was present in 10.9% and growth failure in 20.9% of Crohn's disease cases. Steroids were the initial therapy in 84.2%, 5-amino salicylic acid in 67.3% and exclusive enteral nutrition (EEN) in 1.3% cases. Overall, immunomodulators and biologics were given to 84.3 and 17.9% cases, respectively, and 2.9% cases underwent surgery. Very early onset IBD (VEOIBD) was seen in 60 (19.2%) children. IBDU was commoner in the VEOIBD than the older-PIBD (18/60 vs 4/253; P < 0.001). VEOIBD-Crohn's disease patients more often had isolated colonic disease than the older Crohn's disease (45.4% vs 11.8%; P < 0.001). Prevalence of perianal disease, EIM, therapeutic requirements and outcome were not different between VEOIBD and older-PIBD.

CONCLUSION

Disease location and phenotype of PIBD in Indian children is similar to the children from the west. However, the therapeutic options of EEN, biologics and surgery are underutilized. VEOIBD accounted for 19.2% of PIBD.

Genetic Predictors of Long-term Response to Antitumor Necrosis Factor Agents in Pediatric Inflammatory Bowel Disease

OBJECTIVES

Inflammatory bowel disease (IBD) is more complex in children and they will have to live with the disease for much longer. For this reason, it is necessary to optimize treatment. The polymorphisms associated with the response to anti-tumor necrosis factor (TNF) drugs in adults with IBD have not been analyzed in children. The aim of the study was to identify genetic variants associated with the long-term response to anti-TNF drugs in children with IBD.

METHODS

An observational, longitudinal, ambispective cohort's study was conducted. We recruited 209 anti-TNF-treated children diagnosed with IBD and genotyped 21 polymorphisms previously studied in adults with Crohn disease (CD) using real-time PCR. The association between single-nucleotide polymorphisms (SNPs) and time-to-failure was analyzed using the log-rank test.

RESULTS

After multivariate analysis, 3 SNPs in IL10, IL17A and IL6 were significantly associated with response to anti-TNF treatment among patients diagnosed with CD (rs1800872-HR, 4.749 (95% confidence interval [CI] 1.156-19.517), P value < 0.05; rs2275913-HR, 0.320 [95% CI 0.111-0.920], P value  < 0.05; and rs10499563-HR, 0.210 [95% CI 0.047-0.947], P value 0.05, respectively). None of these SNPs were associated with response to infliximab in adults diagnosed with CD. Among patients diagnosed with ulcerative colitis (UC), 1 SNP in LY96 was significantly associated with response to anti-TNF treatment (rs-11465996-HR, 10.220 [95% CI 1.849-56.504] P value < 0.05).

CONCLUSIONS

Genotyping of these DNA variants before starting treatment may help to identify children who are long-term responders to anti-TNF drugs, and thus tailor treatment of pediatric IBD.

Therapeutic Drug Monitoring-guided High-dose Infliximab for Infantile-onset Inflammatory Bowel Disease: A Case Series

Very early-onset inflammatory bowel disease (IBD) and specifically infantile-onset IBD patients, are characterized by high rates of extensive colonic involvement and decreased response rate to standard therapeutic regimens, including infliximab (IFX). We present a case series of 4 patients with infantile-onset IBD achieving clinical and biologic remission, after treatment with therapeutic drug monitoring (TDM)-guided accelerated high-dose IFX therapy. All patients were treated with accelerated high-dose IFX induction of up to 22 mg/kg. In 3 of these patients, accelerated high-dose IFX was used following failure of intensified standard dose induction. All patients achieved remission following re-induction.We suggest that children with infantile-onset IBD may require a TDM-guided accelerated high-dose IFX induction and maintenance treatment in order to achieve and maintain remission. Personalized approach in these patients is essential in order to prevent underdosing and to avoid inappropriate interpretation of treatment failure.