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Inflammatory bowel disease (IBD) chronicity results from memory T helper cell (Tmem) reactivation. Identifying patient-specific immunotypes is crucial for tailored treatment. We conducted a comprehensive study integrating circulating immune proteins and circulating Tmem, with intestinal tissue histology and mRNA analysis, in therapy-naïve pediatric IBD (Crohn's disease, CD: n = 62; ulcerative colitis, UC: n = 20; age-matched controls n = 43), and after 10-12 weeks' induction therapy. At diagnosis, plasma protein profiles unveiled two UC and three CD clusters with distinct disease courses. UC patients displayed unchanged circulating Tmem, while CD exhibited increased frequencies of gut-homing ex-Th17, known for high IFN-γ production. UC#2 had elevated Th17/neutrophil-pathway-related proteins and severe disease, with higher endoscopic and histological damage and Th17/neutrophil infiltration. Although both UC#1 and UC#2 responded to therapy, UC#2 required earlier immunomodulation. CD#3 had lower plasma protein concentrations, especially IFN-γ pathway proteins, fewer gut-homing ex-Th17 and clinically milder disease, confirmed by intestinal gene expression. CD#1 and CD#2 had comparably high Th1-related immune profiles, but CD#1 exhibited higher concentrations of proteins previously associated with poorer prognosis. Both CD clusters responded to induction therapy, with similar one-year outcomes. This study highlights feasibility of discriminating patient-specific immunotypes in IBD, advancing our understanding of immune pathogenesis, needed for tailored treatment strategies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Variants in EFEMP1, encoding Fibulin-3, were previously reported as a rare cause of heritable connective tissue disorder (HCTD) with recurrent hernias and joint hypermobility. We report three new cases with biallelic or monoallelic EFEMP1 variants and severe hernia phenotypes. Two male siblings of 10 and 13 years old presented with marfanoid habitus, recurrent inguinal and umbilical hernias, generalized joint hypermobility, and scoliosis. Parents and halfsiblings reported joint hypermobility and umbilical hernias. The eldest boy died at age 16 from incarcerated gastrointestinal herniation complicated by gastric and bowel necrosis with perforation. Autopsy revealed widespread intestinal diverticula. Immunohistochemistry of skin and fascia tissue did not reveal any abnormalities, including normal staining of elastic fibers. Both siblings harbored compound heterozygous likely pathogenic EFEMP1 variants (c.1320 + 2T > A, p.? and c.698G > A, p.Gly233Asp). An unrelated 58-year-old male had marfanoid features, high myopia, recurrent diaphragmatic and inguinal hernias, and chronic gastrointestinal dilatation with severe malabsorption. Both his dizygotic twin-brother and mother had recurrent hernias and high myopia. This man died at 59 years of age, and autopsy showed extensive diaphragmatic herniation, bowel diverticula, and pulmonary emphysema. A heterozygous EFEMP1 splice-variant (c.81 + 1G > A, p.?) was identified, causing exon skipping leading to a start-loss. Targeted genome reanalysis nor RNA-sequencing revealed a second variant at the other allele. The reported individuals expand the clinical and pathological phenotypes of EFEMP1-related disease, a distinct entity within the spectrum of HCTD. The severe and recurrent hernias, gastrointestinal dilatation, and diverticulosis result in an increased risk for life-threatening complications, demanding early recognition and close monitoring., Competing Interests: Competing interests: The authors declare no competing interests. Ethical approval and consent to participate: All subjects or legal guardians provided written informed consent for publication of this manuscript. Specific informed consent was obtained for the publication of clinical pictures. Standard postmortem investigation was performed upon consent by the relatives of the deceased. The study was conducted in accordance with the 1984 Declaration of Helsinki and its subsequent revisions., (© 2024. The Author(s), under exclusive licence to European Society of Human Genetics.)

Introduction: Children with inflammatory bowel disease (IBD) need surgery whenever medical therapy fails. The postoperative course is frequently accompanied by symptoms suggestive of infection, such as fever. The aim of our study was to analyze the postoperative course after bowel resection in pediatric IBD patients in relation to postoperative infections., Methods: All our pediatric IBD patients who underwent a bowel resection between 2012 and 2022 were retrospectively reviewed. Clinical data regarding surgery and the postoperative course were analyzed. The primary outcomes were signs and symptoms indicative of infection, such as fever, surgical site infection, and abscesses., Main Results: One hundred patients underwent an IBD-related resection, of whom 69 for Crohn's disease. A total of 42 postoperative infections occurred in 26 patients, most commonly a superficial surgical site infection (38 %). Out of 48 patients who experienced postoperative fever, 52 % had an actual infection, compared to 2 % of those without fever (p < 0.001). Preoperative use of immunomodulating therapy was not associated with higher complication rates. In 35 of 48 patients with fever (73 %) laboratory tests were done as a consequence of postoperative fever, with no differences in complication rates between patients with extremely high (>200 mg/L) and high (<200 mg/L) C-reactive protein levels., Conclusions: Occurring in over a quarter of patients, postoperative infections are common in children after undergoing IBD-related bowel resection. Postoperative fever is indicative of an infection in half of the patients. Laboratory tests, such as serum C-reactive protein, do not seem to contribute to differentiating between complicated and non-complicated course after surgery in these patients., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

CD4 + memory T cell (T M ) reactivation drives chronicity in inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis. Defects driving loss of T M regulation likely differ between patients but remain undefined. In health, approximately 40 % of circulating gut-homing CD38 + T M express co-inhibitory receptor T-cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT). TIGIT + CD38 + T M have regulatory function while TIGIT neg CD38 + T M are enriched in IFN-γ-producing cells. We hypothesized TIGIT neg CD38 + T M are inflammatory and drive disease in a subgroup of IBD patients. We characterized TIGIT + CD38 + T M in a uniquely large cohort of pediatric IBD patients from time of diagnosis into adulthood. Circulating TIGIT neg CD38 + T M frequencies were higher in a subgroup of therapy-naïve CD patients with high plasma IFN-γ and a more severe disease course. TIGIT neg CD38 + T M were highly enriched in HLA-DR + and ex-Th17/Th1-like cells, high producers of IFN-γ. Cultures of healthy-adult-stimulated T M identified IL-12 as the only IBD-related inflammatory cytokine to drive the pathogenic ex-Th17-TIGIT neg CD38 + phenotype. Moreover, IL12RB2 mRNA expression was higher in TIGIT neg CD38 + T M than TIGIT + CD38 + T M , elevated in CD biopsies compared to controls, and correlated with severity of intestinal inflammation. Overall, we argue that in a subgroup of pediatric CD, increased IL-12 signaling drives reprogramming of Th17 to inflammatory Th1-like TIGIT neg CD38 + T M and causes more severe disease., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: FMR, NMC, JCE, and LdR are involved in industry-sponsored studies/investigator-initiated studies/consultancy or received research support from AbbVie, BIOGEN, BMS, ABBVIE, CELGENE, Danone, Eli Lilly, Janssen, MeadJohnson, Medtronic, MSD, MSD France, Nestlé Health Science, Nestlé Nutrition Institute, Pfizer and TAKEDA. All other authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background and Aims: The effectiveness of transition programs from paediatric to adult healthcare in adolescents with inflammatory bowel disease is not clear, as prospective studies using validated outcome measures for transition are lacking. This study aimed to develop and validate a quantitative Transition Success Score, and to apply it in a multicenter setting to assess the effectiveness of transitional care., Methods: The Top 10 outcome items related to successful transition, identified through an international Delphi study with IBD stakeholders, were integrated into a generic questionnaire, the Transition Success Score. In a prospective, multicenter study, Transition Success Score was scored by adult healthcare providers, young adult patients and caregivers, 9-15 months after transfer of care., Results: In seven Dutch hospitals, 160 patients completed the Transition Success Score. The mean score was 25 (range 17-27), 25.6% of patients achieving maximum score. Hypothesis testing for construct validity revealed significant associations with characteristics related to transitional care, such as knowledge, independence, and quality of life (p <0.005). Structural validation indicated the score was most effective at discerning lower levels of transition success. Internal consistency was acceptable (0.64). High disease burden, exacerbation during or after transfer, and certain personality profiles were associated with lower scores., Conclusions: The Transition Success Score serves as a quantitative tool to evaluate the effectiveness of transitional care interventions and to identify inflammatory bowel disease patients at risk of encountering challenges during the transition to adult healthcare., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation.)

Transition services-programs that support adolescents and young adults (AYAs) as they move from a child-centered to a more autonomous, adult-orientated healthcare system-have been associated with improved short- and long-term healthcare outcomes. Unfortunately, there is a paucity of evidence exploring transition services within the neurogastroenterology and motility (NGM) field. The overall aim of this article, endorsed by the American Neurogastroenterology and Motility Society and European Society of Neurogastroenterology and Motility, is to promote a discussion about the role of transition services for patients with NGM disorders. The AYAs addressed herein are those who have: (a) a ROME positive disorder of gut-brain interaction (DGBI), (b) a primary or secondary motility disorder (including those with motility disorders that have been surgically managed), or (c) an artificial feeding requirement (parenteral or enteral tube feeding) to manage malnutrition secondary to categories (a) or (b). The issues explored in this position paper include the specific physical and psychological healthcare needs of patients with NGM disorders; key healthcare professionals who should form part of a secondary care NGM transition service; the triadic relationship between healthcare professionals, caregivers, and patients; approaches to selecting patients who may benefit most from transition care; methods to assess transition readiness; and strategies with which to facilitate transfer of care between healthcare professionals. Key areas for future research are also addressed, including the construction of NGM-specific transition readiness questionnaires, tools to assess post-transfer healthcare outcomes, and educational programs to train healthcare professionals about transition care in NGM., (© 2024 The Author(s). Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Background and Aims: We sought to define the prevalence and to characterize possible predictive factors of Crohn's disease (CD) occurring in children with ulcerative colitis (UC) after ileal pouch-anal anastomosis (IPAA)., Methods: This was a multicenter, retrospective study including 15 centers of the Porto IBD group of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition. Children with a confirmed diagnosis of UC undergoing colectomy with IPAA and a minimal follow up of 6 months were identified. The following data were collected: demographic data; endoscopic and histologic data; disease activity; laboratory exams; therapeutic history; indication for surgery, type, and timing; and IPAA functional outcomes and complications. In de novo CD cases, time of diagnosis, phenotype, location, and therapies were gathered., Results: We identified 111 UC children undergoing IPAA from January 2008 to June 2018 (median age at colectomy: 13 years; age range: 1-18 years; female/male: 59/52). The median time from diagnosis to colectomy was 16 (range, 0-202) months. At the last follow-up, 40 (36%) of 111 children developed pouchitis. The criteria for de novo CD were met in 19(17.1%) of 111 children with a 25-month median (range, 3-61 months). At last follow-up, 12 (63.1%) of 19 were treated with biologics and in 5 (26.3%) of 19 children, the pouch was replaced with definitive ileostomy. In a multivariable logistic regression model, decreased preoperative body mass index z scores (odds ratio, 2.2; 95% confidence interval, 1.1-4.4; P = .01) resulted as the only variable associated with CD development., Conclusions: Children with UC undergoing IPAA carry a high risk of developing subsequent CD. De novo CD cases showed decreased preoperative body mass index z scores, identifying a poor nutritional status as a possible predictive factor., (© The Author(s) 2023. Published by Oxford University Press on behalf of Crohn’s & Colitis Foundation. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background and Purpose: In the Netherlands, the 2022 Quality Standard 'Youth in transition from paediatric to adult care' underscores the importance of structured transitional care for young adults with chronic health conditions. Despite this emphasis, detailed knowledge about transition programs and their successful elements remains sparse. This study aims to bridge this gap by exploring nurse-led transition clinics that had successfully implemented core interventions such as a transition coordinator, warm handover, and individual transition plans., Methods: Employing a mixed-methods approach, this study integrated semi-structured interviews with 15 healthcare professionals from both paediatric and adult care across six transition clinics, and surveys from 54 young adults who had transitioned within the last three years. The 'On Your Own Feet Framework' guided the evaluation of transitional care practices. Thematic analysis was applied to qualitative data, while descriptive and inferential statistics were used to analyse quantitative data., Results: The study revealed a strong dedication among healthcare professionals to ensuring smooth transitions and effective collaboration between paediatric and adult care. The young adults reported high satisfaction with their transitions, particularly appreciating the continuity of care and the pivotal role of nurses and nurse practitioners as transition coordinators. However, challenges such as engaging young adults, resource allocation, and financial complexities were noted, alongside areas for improvement including shared decision-making and managing parental involvement. Motivation and collaboration among staff were identified as facilitating factors., Discussion and Conclusion: Our findings emphasize the vital role of nurse-led transition clinics in enhancing healthcare transitions for young adults in the Netherlands, aligning with the principles outlined in the Quality Standard and the On Your Own Feet Framework. While high satisfaction levels with current practices suggest a positive impact, they also highlight that ongoing improvement and adaptation are needed to overcome identified challenges. Successful healthcare transition requires a comprehensive, collaborative approach involving patients, families, and healthcare professionals, supported by organizational and systemic frameworks. This study contributes to a nuanced understanding of transitional care, suggesting a path forward for integrating these practices into standard care models., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

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., (Copyright © 2024 by the American Academy of Pediatrics.)

Objectives: Paediatric and adult inflammatory bowel disease (pIBD, aIBD) patients may lose response to anti-tumour necrosis factor (TNF) treatment within the first year. Adult-extrapolated weight-based dosing is incorrect in children, due to age-related pharmacokinetic differences. We investigated biomarkers for initial and maintenance of response to infliximab (IFX) or adalimumab (ADA), comparing pIBD and aIBD patients., Methods: In this prospective, observational study, pIBD (n = 24) and aIBD (n = 21) patients were included when initiating anti-TNF. Escalation from standard dosing and continued anti-TNF at 12 and 18 months were assessed. Biomarkers included clinical laboratory parameters, faecal calprotectin (FCP) and IFX trough levels (TLs). Plasma proteomics was performed in pIBD., Results: During our study, treatment escalation (in clinical loss of response) occurred more common in pIBD versus aIBD (p = 0.02). We established that IFX therapy escalation in pIBD patients was not due to low infliximab levels. We identified 9 pro-inflammatory proteins that were elevated in patients losing response., Conclusion: Anti-TNF exposure-response relationship may be different in pIBD versus aIBD. No biomarkers for maintained response were identified, but 9 inflammatory proteins were of interest as potential predictors for loss of response in pIBD., (© 2024 The Authors. Journal of Pediatric Gastroenterology and Nutrition published by Wiley Periodicals LLC on behalf of European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Background: Data on cost-effectiveness of first-line infliximab in paediatric patients with Crohn's disease are limited. Since biologics are increasingly prescribed and accompanied by high costs, this knowledge gap needs to be addressed., Aim: To investigate the cost-effectiveness of first-line infliximab compared to conventional treatment in children with moderate-to-severe Crohn's disease., Methods: We included patients from the Top-down Infliximab Study in Kids with Crohn's disease randomised controlled trial. Children with newly diagnosed moderate-to-severe Crohn's disease were treated with azathioprine maintenance and either five induction infliximab (biosimilar) infusions or conventional induction treatment (exclusive enteral nutrition or corticosteroids). Direct healthcare consumption and costs were obtained per patient until week 104. This included data on outpatient hospital visits, hospital admissions, drug costs, endoscopies and surgeries. The primary health outcome was the odds ratio of being in clinical remission (weighted paediatric Crohn's disease activity index<12.5) during 104 weeks., Results: We included 89 patients (44 in the first-line infliximab group and 45 in the conventional treatment group). Mean direct healthcare costs per patient were €36,784 for first-line infliximab treatment and €36,874 for conventional treatment over 2 years (p = 0.981). The odds ratio of first-line infliximab versus conventional treatment to be in clinical remission over 104 weeks was 1.56 (95%CI 1.03-2.35, p = 0.036)., Conclusions: First-line infliximab treatment resulted in higher odds of being in clinical remission without being more expensive, making it the dominant strategy over conventional treatment in the first 2 years after diagnosis in children with moderate-to-severe Crohn's disease., Trial Registration Number: NCT02517684., (© 2024 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

Objectives: Transition readiness can predict a successful transition from pediatric to adult care. This study aimed to validate and develop age-dependent reference scores for the (Dutch version of) Transition Readiness Assessment Questionnaire (TRAQ), in adolescents and young adults (AYAs) with inflammatory bowel disease (IBD)., Methods: TRAQ has 20 items (score 1-5) distributed over 5 domains (total sum score 100) and is completed by AYAs. Following the COnsensus-based Standards for the selection of health Measurement INstruments methodology, we conducted the translation, back-to back translation, pretesting, and validation of the final Dutch version of TRAQ (TRAQ-NL) questionnaire. We used a Rasch model for structural validation, hypothesis testing for construct validity, and Cronbach alpha to demonstrate reliability. Reference scores were calculated using percentiles., Results: Two hundred fifty TRAQ questionnaires were evaluated in 136 AYAs with IBD [56% Crohn disease, 58% male, median age 17.5 years (range 15.7-20.4)]. The overall mean item score was 3.87 (range 1.45-5). With good reliability (Cronbach alpha 0.87), TRAQ-NL discriminated well between knowledge levels, especially in the lower levels. Transition readiness was defined as low, moderate, adequate, or excellent in patients with TRAQ percentile scores (PC) <25th (<3.375 mean item score), 25th-50th (3.375-3.9), 50th-90th (3.91-4.7), or >90th (>4.7). Younger patients, concomitant illness, fewer visits to the transition clinic, and parental dependence were associated with significantly lower TRAQ scores., Conclusion: TRAQ(-NL) is reliable and valid, with age-dependent PC to identify (in)adequate transfer readiness. TRAQ can now be more easily used as a patient-reported outcome measure to monitor transition readiness longitudinally in routine care for AYAs IBD patients., Competing Interests: Dr Escher served for a scientific advisory board for Janssen and Abbvie, received a research grant from MSD, and a grant from Abbvie for a transitional care project, not concerning the submitted work. Dr de Ridder has done research consults for Takeda and Abbvie and received a research grant from Pfizer outside the submitted work. van Pieterson received a research nursing grant from Erasmus MC, ECCO, and Dr Falk Pharma for a transitional care project, not concerning the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 by European Society for European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Background: Despite its efficacy, rational guidance for starting/stopping first-line biologic treatment in individual paediatric Crohn's disease [CD] patients is needed. We assessed how serum immune profiles before and after first-line infliximab [FL-IFX] or conventional [CONV] induction therapy associate with disease remission at week 52., Methods: Pre- [n = 86], and 10-14-week post-treatment [n = 84] sera were collected from patients with moderate-to-severe paediatric CD in the TISKids trial, randomized to FL-IFX [n = 48; five 5-mg/kg infusions over 22 weeks] or CONV [n = 43; exclusive enteral nutrition or oral prednisolone]; both groups received azathioprine maintenance. The relative concentrations of 92 inflammatory proteins were determined with Olink Proteomics; fold changes [FC] with |log2FC| > 0.5 after false discovery rate adjustment were considered significant., Results: FL-IFX modulated a larger number of inflammatory proteins and induced stronger suppression than CONV; 18/30 proteins modulated by FL-IFX were not regulated by CONV. Hierarchical clustering based on IFX-modulated proteins at baseline revealed two clusters of patients: CD-hi patients had significantly higher concentrations of 23/30 IFX-modulated proteins [including oncostatin-M, TNFSF14, HGF and TGF-α], and higher clinical disease activity, C-reactive protein and blood neutrophils at baseline than CD-lo patients. Only 24% of CD-hi FL-IFX-treated patients maintained remission without escalation at week 52 vs 58% of CD-lo FL-IFX-treated patients. Similarly, 6% of CD-hi CONV-treated patients achieved remission vs 20% of CONV-treated CD-lo patients. Clustering based on immune profiles post-induction therapy did not relate to remission at week 52., Conclusion: FL-IFX leads to stronger reductions and modulates more immune proteins than CONV. Stratification on pre-treatment profiles of IFX-modulated proteins directly relates to maintenance of remission without treatment escalation., Trial Registration Number: NCT02517684., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation.)

Objectives: Physical activity programs have been suggested as adjunctive therapy in adult inflammatory bowel disease (IBD) patients. We assessed the effects of a 12-week lifestyle intervention in children with IBD., Methods: This study was a randomized semi-crossover controlled trial, investigating a 12-week lifestyle program (3 physical training sessions per week plus personalized healthy dietary advice) in children with IBD. Endpoints were physical fitness (maximal and submaximal exercise capacity, strength, and core stability), patient-reported outcomes (quality of life, fatigue, and fears for exercise), clinical disease activity (fecal calprotectin and disease activity scores), and nutritional status (energy balance and body composition). Change in maximal exercise capacity (peak VO 2 ) was the primary endpoint; all others were secondary endpoints., Results: Fifteen patients (median age 15 [IQR: 12-16]) completed the program. At baseline, peak VO 2 was reduced (median 73.3% [58.8-100.9] of predicted). After the 12-week program, compared to the control period, peak VO 2 did not change significantly; exercise capacity measured by 6-minute walking test and core-stability did. While medical treatment remained unchanged, Pediatric Crohn's Disease Activity Index decreased significantly versus the control period (15 [3-25] vs 2.5 [0-5], P = 0.012), and fecal calprotectin also decreased significantly but not versus the control period. Quality of life (IMPACT-III) improved on 4 out of 6 domains and total score (+13 points) versus the control period. Parents-reported quality of life on the child health questionnaire and total fatigue score (PedsQoL Multidimensional Fatigue Scale) also improved significantly versus the control period., Conclusions: A 12-week lifestyle intervention improved bowel symptoms, quality of life, and fatigue in pediatric IBD patients., Competing Interests: J.C.E. received institutional research support from MSD, AbbVie, and Janssen. L.E.M.v.d.B. has received research support from “Maag Darm Lever Stichting,” “Stichting Vrienden van Sophia,” and the “Beatrix spierfonds.” The remaining authors report no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer on behalf of European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Background: Maintaining of remission early in the disease course of Crohn's disease (CD) is essential and has major impact on the future prognosis. This study aimed to identify baseline predictors to develop model allowing stratification of patients who will not benefit from long-term azathioprine (AZA) treatment and will require more intensive therapy., Methods: This study was designed to develop clinical prediction rule using retrospective data analysis of pediatric CD patients included in prospective inception cohort. Clinical relapse was defined as necessity of re-induction of remission. Sequence of Cox models was fitted to predict risk of relapse., Results: Out of 1190 CD patients from 13 European centers, 441 were included, 50.3% patients did not experience clinical relapse within 2 years of AZA treatment initiation. Median time to relapse was 2.11 (CI 1.59-2.46) years. Of all the tested parameters available at diagnosis, six were significant in multivariate analyses: C-reactive protein (p = 0.038), body mass index Z-score >0.8 SD (p = 0.002), abnormal sigmoid imaging (p = 0.039), abnormal esophageal endoscopy (p = 0.005), ileocolonic localization (p = 0.023), AZA dose in specific age category (p = 0.031)., Conclusions: Although the possibility of predicting relapse on AZA treatment appears limited, we developed predictive model based on six baseline parameters potentially helpful in clinical decision., Impact: The possibility of predicting relapse on AZA treatment appears to be possible but limited. We identified six independent predictors available at diagnosis of early AZA/6-MP treatment failure in pediatric CD patients. Using combination of these factors, a model applicable to clinical practice was created. A web-based tool, allowing estimation of individual relapse risk in pediatric CD patients on a particular therapeutic regimen, has been developed., (© 2022. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)

To induce remission in luminal paediatric Crohn's disease (CD), the ESPGHAN/ECCO guideline recommends treatment with exclusive enteral nutrition (EEN) or oral corticosteroids. In newly diagnosed moderate-to-severe paediatric CD patients, we determined the proportion of patients in which EEN or corticosteroids induced remission and maintained remission on azathioprine monotherapy. We included patients from the "TISKids" study assigned to the conventional treatment arm. Patients were aged 3-17 years and had new-onset, untreated luminal CD with weighted paediatric CD activity index (wPCDAI) > 40. Induction treatment consisted of EEN or oral corticosteroids; all received azathioprine maintenance treatment from start of treatment. The primary outcome of this study was endoscopic remission defined as a SES-CD score < 3 without treatment escalation at week 10. Secondary outcomes included proportion of patients without treatment escalation at week 52. In total, 27/47 patients received EEN and 20/47 corticosteroids. At baseline, patient demographics and several inflammation parameters were similar between the two treatment groups. At 10 weeks, clinical remission rates were 7/23 (30%) for EEN and 7/19 (37%) for corticosteroids (p = 0.661). Twenty-nine of 47 consented to endoscopy at 10 weeks, showing endoscopic remission rates without treatment escalation in 2/16 (13%) of EEN-treated patients and in 1/13 (8%) of corticosteroid-treated patients (p = 1.00). At week 52, 23/27 (85%) EEN-treated patients received treatment escalation (median 14 weeks) and 13/20 (65%) corticosteroid-treated patients (median 27 weeks), p = 0.070.Conclusion: In children with moderate-to-severe newly diagnosed CD, induction treatment with EEN or CS regularly is insufficient to achieve endoscopic remission without treatment escalation at week 10. Trial registration number: NCT02517684 What is Known: • Endoscopic remission is associated with a low risk of disease progression. • FL-IFX was superior to conventional treatment in achieving and maintaining remission in paediatric patients with moderate-to-severe CD the first year from diagnosis. What is New: • In children with newly diagnosed moderate-to-severe CD, clinical remission rates and endoscopic remission rates without treatment escalation at week 10 were 30% and 13% after EEN and 37% and 8% after corticosteroid induction treatment. • The current treatment target was often not achieved by either EEN or corticosteroid induction treatment after bridging to azathioprine., (© 2022. The Author(s).)

Chronic intestinal inflammation underlies inflammatory bowel disease (IBD). Previous studies indicated alterations in the cellular immune system; however, it has been challenging to interrogate the role of all immune cell subsets simultaneously. Therefore, we aimed to identify immune cell types associated with inflammation in IBD using high-dimensional mass cytometry. We analyzed 188 intestinal biopsies and paired blood samples of newly-diagnosed, treatment-naive patients ( n =42) and controls ( n =26) in two independent cohorts. We applied mass cytometry (36-antibody panel) to resolve single cells and analyzed the data with unbiased Hierarchical-SNE. In addition, imaging-mass cytometry (IMC) was performed to reveal the spatial distribution of the immune subsets in the tissue. We identified 44 distinct immune subsets. Correlation network analysis identified a network of inflammation-associated subsets, including HLA-DR + CD38 + EM CD4 + T cells, T regulatory-like cells, PD1 + EM CD8 + T cells, neutrophils, CD27 + TCRγδ cells and NK cells. All disease-associated subsets were validated in a second cohort. This network was abundant in a subset of patients, independent of IBD subtype, severity or intestinal location. Putative disease-associated CD4 + T cells were detectable in blood. Finally, imaging-mass cytometry revealed the spatial colocalization of neutrophils, memory CD4 + T cells and myeloid cells in the inflamed intestine. Our study indicates that a cellular network of both innate and adaptive immune cells colocalizes in inflamed biopsies from a subset of patients. These results contribute to dissecting disease heterogeneity and may guide the development of targeted therapeutics in IBD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 van Unen, Ouboter, Li, Schreurs, Abdelaal, Kooy-Winkelaar, Beyrend, Höllt, Maljaars, Mearin, Mahfouz, Witte, Clemens, Abraham, Escher, Lelieveldt, Pascutti, van der Meulen – de Jong and Koning.)

Introduction: Physical activity is associated with many physiological and psychological health benefits across the lifespan. Children with a chronic disease often have lower levels of daily physical activity, and a decreased exercise capacity compared to healthy peers. In order to learn more about limitations for physical activity, we investigate children with four different chronic diseases: children with a Fontan circulation, children with Broncho Pulmonary Dysplasia (BPD), Pompe disease and inflammatory bowel disease (IBD). Each of these diseases is likely to interfere with physical activity in a different way. Knowing the specific limitations for physical activity would make it possible to target these, and increase physical activity by a personalized intervention. The aim of this study is to first investigate limitations for physical activity in children with various chronic diseases. Secondly, to measure the effects of a tailored exercise intervention, possibly including a personalized dietary advice and/or psychological counseling, on exercise capacity, endurance, quality of life, fatigue, fear for exercise, safety, muscle strength, physical activity levels, energy balance, and body composition. Methods and Analysis: This randomized crossover trial will aim to include 72 children, aged 6-18 years, with one of the following diagnosis: a Fontan circulation, BPD, Pompe disease and IBD. Eligible patients will participate in the 12-week tailored exercise intervention and are either randomized to start with a control period or start with the intervention. The tailored 12-week exercise interventions, possibly including a personalized dietary advice and/or psychological counseling, will be designed based on the found limitations for physical activity in each disease group during baseline measurements by the Rotterdam Exercise Team. Effects of the tailored training interventions will be measured on the following endpoints: exercise capacity (measured by cardiopulmonary exercise test), endurance, physical activity levels, muscle strength, quality of life, fatigue, fear for exercise, disease activity, cardiac function (in children with a Fontan circulation), energy balance, and body composition. Ethics and Dissemination: Conducted according to the Declaration of Helsinki and Good Clinical Practice. Medical-ethical approval was obtained. Trial Registration Number: NL8181, https://www.trialregister.nl/trial/8181., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Scheffers, Helbing, Utens, Dieleman, Dulfer, Noske, van den Broek, Walet, Olieman, Escher, Pijnenburg, van der Ploeg and van den Berg.)

Objectives: Disease knowledge is important in adolescents with inflammatory bowel disease (IBD) transitioning to adult care. We developed an IBD-specific knowledge questionnaire, the Rotterdam Transition Test (RTT), and aimed to validate this tool., Methods: This is a prospective longitudinal validation study. The RTT has 25 open questions on IBD, medication, lifestyle, and transition to adult care. A scoring model was developed, and inter-rater agreement was assessed. Using a Rasch model, we determined the difficulty and performance of the questions. Cronbach alpha was used to demonstrate reliability. Patient factors (age, disease, education, medication use, illness acceptance, and independence) were correlated to RTT score., Results: A total of 207 RTTs were evaluated in 111 adolescent IBD patients. The scoring model showed a kappa score of >0.61 for all questions. Reliability with Cronbach alpha was good (0.81). Mean total result of the RTT was 58% (girls) and 55% (boys) of maximal score.The RTT discriminated well between the different levels of knowledge. Knowledge scores increased in patients who did repeated RTTs during the transition period. Male sex, low educational level, disease acceptance issues, and dependence on parents associated with a significantly lower total RTT score. Prednisone use within 3 months and treatment without biologics associated with significantly higher RTT scores. Disease activity was not a significant factor., Conclusions: The RTT is a reliable and valid tool to assess IBD knowledge. The RTT can be used to detect and discuss knowledge gaps in adolescents with IBD transitioning to adult healthcare., Competing Interests: J.C.E. served for a scientific advisory board for Janssen and Abbvie, and received a research grant from MSD, outside the submitted work. L.d.R. has done research consults for Celltrion and Abbvie, received grants from Pfizer outside the submitted work. J.v.d.W. served as a speaker for Celltrion, on the advisory board for Norgine (personal fees), and received research funding from Pfizer outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2021 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Objective: In newly diagnosed paediatric patients with moderate-to-severe Crohn's disease (CD), infliximab (IFX) is initiated once exclusive enteral nutrition (EEN), corticosteroid and immunomodulator therapies have failed. We aimed to investigate whether starting first-line IFX (FL-IFX) is more effective to achieve and maintain remission than conventional treatment., Design: In this multicentre open-label randomised controlled trial, untreated patients with a new diagnosis of CD (3-17 years old, weighted Paediatric CD Activity Index score (wPCDAI) >40) were assigned to groups that received five infusions of 5 mg/kg IFX at weeks 0, 2, 6, 14 and 22 (FL-IFX), or EEN or oral prednisolone (1 mg/kg, maximum 40 mg) (conventional). The primary outcome was clinical remission on azathioprine, defined as a wPCDAI <12.5 at week 52, without need for treatment escalation, using intention-to-treat analysis., Results: 100 patients were included, 50 in the FL-IFX group and 50 in the conventional group. Four patients did not receive treatment as per protocol. At week 10, a higher proportion of patients in the FL-IFX group than in the conventional group achieved clinical (59% vs 34%, respectively, p=0.021) and endoscopic remission (59% vs 17%, respectively, p=0.001). At week 52, the proportion of patients in clinical remission was not significantly different (p=0.421). However, 19/46 (41%) patients in the FL-IFX group were in clinical remission on azathioprine monotherapy without need for treatment escalation vs 7/48 (15%) in the conventional group (p=0.004)., Conclusions: FL-IFX was superior to conventional treatment in achieving short-term clinical and endoscopic remission, and had greater likelihood of maintaining clinical remission at week 52 on azathioprine monotherapy., Trial Registration Number: ClinicalTrials.gov Registry (NCT02517684)., Competing Interests: Competing interests: LdR reports grants from ZonMW, ECCO, Crocokids and Pfizer and consultancy fees from Abbvie, during the conduct of the study. MAA received a consultant fee from Abbvie, outside the submitted work. MAC reports grants from ZonMw and Crocokids, and grants and non-financial support from Pfizer during the conduct of the study. IH received a payment/honorarium for lectures from BioGaia, Nutricia, Oktal pharma, Nestle, Biocodex and AbelaPharm. K-LK received consultant fees from Abbvie, Biocodex, Ferring, MSD and Tillotts Pharma, and research grants from the Pediatric Research Foundation (Finland) and the Helsinki University Research Fund, outside the submitted work. TH received a consultant fee from Pfizer, outside the submitted work. JS reports personal fees from Nutricia, outside the submitted work. MPvW reports personal fees from Danone and Laborie, outside the submitted work. STAT-R received a consultant fee from Pfizer, outside the submitted work. JCE received consultant fees from Abbvie and Janssen, as well as research support from MSD and Nutricia., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Single genetic mutations predispose to very early onset inflammatory bowel disease (VEO-IBD). Here, we identify a de novo duplication of the 10p15.1 chromosomal region, including the IL2RA locus, in a 2-year-old girl with treatment-resistant pancolitis that was brought into remission by colectomy. Strikingly, after colectomy while the patient was in clinical remission and without medication, the peripheral blood CD4:CD8 ratio was constitutively high and CD25 expression was increased on circulating effector memory, Foxp3 + , and Foxp3 neg CD4 + T cells compared to healthy controls. This high CD25 expression increased IL-2 signaling, potentiating CD4 + T-cell-derived IFNγ secretion after T-cell receptor (TCR) stimulation. Restoring CD25 expression using the JAK1/3-inhibitor tofacitinib controlled TCR-induced IFNγ secretion in vitro. As diseased colonic tissue, but not the unaffected duodenum, contained mainly CD4 + T cells with a prominent IFNγ-signature, we hypothesize that local microbial stimulation may have initiated colonic disease. Overall, we identify that duplication of the IL2RA locus can associate with VEO-IBD and suggest that increased IL-2 signaling predisposes to colonic intestinal inflammation., (© 2021. The Author(s).)

Competing Interests: Declaration if interests We declare no competing interests.

Objective: The aim of this study was to describe the long-term health outcomes of children born to mothers with inflammatory bowel disease (IBD) and to assess the impact of maternal IBD medication use on these outcomes., Design: We performed a multicentre retrospective study in The Netherlands. Women with IBD who gave birth between 1999 and 2018 were enrolled from 20 participating hospitals. Information regarding disease characteristics, medication use, lifestyle, pregnancy outcomes and long-term health outcomes of children was retrieved from mothers and medical charts. After consent of both parents, outcomes until 5 years were also collected from general practitioners. Our primary aim was to assess infection rate and our secondary aims were to assess adverse reactions to vaccinations, growth, autoimmune diseases and malignancies., Results: We included 1000 children born to 626 mothers (381 (61%) Crohn's disease, 225 (36%) ulcerative colitis and 20 (3%) IBD unclassified). In total, 196 (20%) had intrauterine exposure to anti-tumour necrosis factor-α (anti-TNF-α) (60 with concomitant thiopurine) and 240 (24%) were exposed to thiopurine monotherapy. The 564 children (56%) not exposed to anti-TNF-α and/or thiopurine served as control group. There was no association between adverse long-term health outcomes and in utero exposure to IBD treatment. We did find an increased rate of intrahepatic cholestasis of pregnancy (ICP) in case thiopurine was used during the pregnancy without affecting birth outcomes and long-term health outcomes of children. All outcomes correspond with the general age-adjusted population., Conclusion: In our study, we found no association between in utero exposure to anti-TNF-α and/or thiopurine and the long-term outcomes antibiotic-treated infections, severe infections needing hospital admission, adverse reactions to vaccinations, growth failure, autoimmune diseases and malignancies., Competing Interests: Competing interests: JCE: received financial support as advisory board member from Janssen (DEVELOP registry) and Abbvie (CAPE registry; and research support from MSD, NdB: has served as a speaker for AbbVie and MSD. He has served as consultant and principal investigator for TEVA Pharma BV and Takeda. He has received a (unrestricted) research grant from Falk and Takeda, FH: has served on advisory boards or as speaker for Abbvie, Janssen-Cilag, MSD, Takeda, Celltrion, Teva, Sandoz and Dr Falk Funding (Grants/Honoraria) Dr Falk, Janssen-Cilag, Abbvie, Takeda. Consulting Fees: Celgene, Janssen-Cilag, BO grant van Ferring, Falk, Pfizer, Takeda; speakers Fee: Ferring, MSD; advisory board: Janssen, Takeda, Abbvie, Ferring, Takeda, RW: advisory board Janssen pharmaceuticals, CJvdW: has participated in advisory board and/or received financial compensation from the following companies: MSD, FALK Benelux, Abbott laboratories, Mundipharma Pharmaceuticals, Janssen, Takeda and Ferring during the last 3 years., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

Introduction: The PIBD-classes criteria were developed to standardise the classification of children with inflammatory bowel disease [IBD], from Crohn's disease [CD], through IBD-unclassified [IBD-U], to typical ulcerative colitis [UC]. We aimed to further validate the criteria and to explore possible modifications., Methods: This was a multicentre retrospective cohort study of children diagnosed with IBD with at least 1 year of follow-up. Clinical, radiological, endoscopic, and histological data were recorded at diagnosis and latest follow-up, as well as the 23 items of the PIBD-classes criteria. The PIBD-classes criteria were assessed for redundant items, and a simplified algorithm was proposed and validated on the original derivation cohort from which the PIBD-classes algorithm was derived., Results: Of the 184 included children [age at diagnosis 13 ± 3 years, 55% males], 122 [66%] were diagnosed by the physician with CD, 17 [9%] with IBD-U, and 45 [25%] with UC. There was high agreement between physician-assigned and PIBD-classes generated diagnosis for CD [93%; eight patients moved to IBD-U] and for UC [84%; six moved to IBD-U and one to CD]. A simplified version of the algorithm with only 19 items is suggested, with comparable performance to the original algorithm [81% sensitivity and 81% specificity vs 78% and 83% for UC; and 79% and 95% vs 80% and 95% for CD, respectively]., Conclusions: The PIBD-classes algorithm is a useful tool to facilitate standardised objective classification of IBD subtypes in children. A modified version of the PIBD-classes maintains accuracy of classification with a simplified algorithm., (Copyright © 2020 European Crohn's and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)