BACKGROUND:Iron deficiency anemia (IDA) is the most common extra-intestinal complication in inflammatory bowel disease (IBD). The persistence of iron deficiency in patients living with quiescent IBD remains poorly understood. Given the extensive body of research linking IBD pathogenesis to microbiome disruptions, it is hypothesized that alterations in the microbiota or immune responses may drive the persistence of IDA in quiescent Crohn's disease. This study aimed to determine whether changes in the gut microbiota or immune phenotypes contribute to IDA, while uncovering potential mechanisms driving IDA in quiescent disease. METHODS:This cross-sectional, descriptive, and analytical study utilized 141 samples from pediatric Crohn's disease patients with and without iron deficiency as well as healthy controls for initial 16S microbiome analysis and a smaller subset for Shotgun Metagenomics and immunologic analyses. Fecal and peripheral blood samples were obtained from the Jill Roberts Institute Live Cell Bank. RESULTS:While no major differences were observed in the overall gut microbiome composition between pediatric patients with quiescent Crohn's disease, with or without IDA, notable shifts in specific microbial strains were identified. Specifically, levels of Anaerobutyricum soehngenii and Alistipes shahii were significantly altered. Metagenomic analysis revealed an enrichment of pathways related to short-chain fatty acid metabolism and ascorbate degradation, indicative of functional change in these microbes. CONCLUSIONS:This is the first comprehensive microbiome analysis of quiescent pediatric Crohn's disease with concomitant IDA. The findings indicate modest but significant microbial strain-level differences and associated functional pathways, potentially implicating microbiota-mediated mechanisms in the persistence of IDA.

Interleukin (IL-)23 is a major mediator and therapeutic target in chronic inflammatory diseases that also elicits tissue protection in the intestine at homeostasis or following acute infection1-4. However, the mechanisms that shape these beneficial versus pathological outcomes remain poorly understood. To address this gap in knowledge, we performed single-cell RNA sequencing on all IL-23 receptor-expressing cells in the intestine and their acute response to IL-23, revealing a dominance of T cells and group 3 innate lymphoid cells (ILC3s). Unexpectedly, we identified potent upregulation of the immunoregulatory checkpoint molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) on ILC3s. This pathway was activated by gut microbes and IL-23 in a FOXO1- and STAT3-dependent manner. Mice lacking CTLA-4 on ILC3s exhibited reduced regulatory T cells, elevated inflammatory T cells and more-severe intestinal inflammation. IL-23 induction of CTLA-4+ ILC3s was necessary and sufficient to reduce co-stimulatory molecules and increase PD-L1 bioavailability on intestinal myeloid cells. Finally, human ILC3s upregulated CTLA-4 in response to IL-23 or gut inflammation and correlated with immunoregulation in inflammatory bowel disease. These results reveal ILC3-intrinsic CTLA-4 as an essential checkpoint that restrains the pathological outcomes of IL-23, suggesting that disruption of these lymphocytes, which occurs in inflammatory bowel disease5-7, contributes to chronic inflammation.

Background: Iron deficiency anemia (IDA) is the most common extra-intestinal complication seen in patients living with inflammatory bowel disease (IBD), Given the significant impact on quality of life, anemia must be identified and corrected quickly. Oral and intravenous iron replacement therapies uniquely alter the gut microbiota in patients with IBD. Prior studies have shown the efficacy of oral iron is limited in IBD. Studies of iron absorption capacity in patients with quiescent disease reveal that patients do have the ability to absorb iron; yet it is known that 1 in 5 patients in disease-free remission may still have some measure of iron deficiency anemia on laboratory examination. Therefore, there is an urgent need to understand the etiology of iron deficiency anemia in quiescent pediatric IBD to optimize treatment. There is a lack of research evaluating the microbial, inflammatory, and immunologic factors implicated in iron malabsorption and metabolism in patients with quiescent Crohn’s disease. Given decades of research linking the pathogenesis of IBD to disruptions in the microbiome, it is hypothesized there are differences in the microbiota and immunologic response in patients with quiescent Crohn’s disease that explain the pathogenesis of IDA. Evaluation of these differences will allow for the development of a predictive model used in the treatment of IDA in pediatric Crohn’s disease. We evaluated the impact of the microbiome and immune status on iron regulation in pediatric patients with quiescent Crohn’s disease, specifically seeking to understand if altered compositions in intestinal microbiota or immune phenotypes may explain the etiology of, or mechanism for, iron deficiency anemia in this patient population. Methods: We utilized both cross-sectional, descriptive, and analytical study designs to evaluate stool and serum samples stored in the JRI Live Cell Bank (LCB). 365 samples met the initial inclusion criteria, with an additional 222 sets excluded due to absence of stored stool or due to active disease on histopathologic evaluation. Study participant characteristics were collected. 143 stored samples were included for initial 16S microbiome analysis from 56 male (39.2%) and 87 female (60.8%) study participants, aged three to twenty-one years, with biopsy confirmed, quiescent Crohn’s disease. Comparator groups included similarly matched quiescent Crohn’s disease study participants without iron deficiency anemia as well as healthy pediatric study participants with and without IDA, all of whom were represented in the JRI LCB. Results: We applied Next Generation Sequencing (NGS) and Shotgun Metagenomic Analysis to stool samples. Samples were analyzed for taxonomic composition, alpha diversity (Chao 1 index, Shannon-Wiener index, and Simpson index), and beta diversity (Bray-Curtis dissimilarity and UniFrac distance). We measured hepcidin and interleukin 6 (IL6) levels in stored serum samples. Results obtained were compared against reference datasets for healthy gut microbiome as well as that associated with iron deficiency anemia without concomitant IBD. Conclusions: To our knowledge, this is the first study to utilize microbiome analysis in quiescent pediatric Crohn’s disease with concomitant IDA to further identify etiologies of IDA in quiescent pediatric Crohn’s disease, which may then be targeted in the management of iron deficiency.

Microbial colonization of the mammalian intestine elicits inflammatory or tolerogenic T cell responses, but the mechanisms controlling these distinct outcomes remain poorly understood, and accumulating evidence indicates that aberrant immunity to intestinal microbiota is causally associated with infectious, inflammatory and malignant diseases1–8. Here we define a critical pathway controlling the fate of inflammatory versus tolerogenic T cells that respond to the microbiota and express the transcription factor RORγt. We profiled all RORγt+ immune cells at single-cell resolution from the intestine-draining lymph nodes of mice and reveal a dominant presence of T regulatory (Treg) cells and lymphoid tissue inducer-like group 3 innate lymphoid cells (ILC3s), which co-localize at interfollicular regions. These ILC3s are distinct from extrathymic AIRE-expressing cells, abundantly express major histocompatibility complex class II, and are necessary and sufficient to promote microbiota-specific RORγt+ Treg cells and prevent their expansion as inflammatory T helper 17 cells. This occurs through ILC3-mediated antigen presentation, αV integrin and competition for interleukin-2. Finally, single-cell analyses suggest that interactions between ILC3s and RORγt+ Treg cells are impaired in inflammatory bowel disease. Our results define a paradigm whereby ILC3s select for antigen-specific RORγt+ Treg cells, and against T helper 17 cells, to establish immune tolerance to the microbiota and intestinal health. ILC3s expressing MHC class II control the fate of inflammatory versus tolerogenic T cells that respond to the microbiota by selecting for antigen-specific RORγt+ Treg cells and against TH17 cells, establishing intestinal homoeostasis.

Microbial colonization of the mammalian intestine elicits inflammatory or tolerogenic T cell responses, but the mechanisms controlling these distinct outcomes remain poorly understood and accumulating evidence indicates that aberrant immunity to intestinal microbiota is causally associated with infectious, inflammatory, and malignant diseases 1–8 . Here, we define a critical pathway controlling the fate of inflammatory versus tolerogenic T cells that are specific for the microbiota and express the transcription factor RORγt. We profiled all RORγt + immune cells at single cell resolution from the intestine-draining lymph nodes of mice and reveal a dominant presence of Tregs and lymphoid tissue-induced (LTi)-like group 3 innate lymphoid cells (ILC3s), which co-localize at interfollicular regions. These ILC3s have interconverting potential with RORγt + extrathymic Aire-expressing cells, abundantly express major histocompatibility complex class II, and are necessary and sufficient to promote microbiota-specific RORγt + Tregs and prevent their expansion as inflammatory T helper (Th)17 cells. This occurs through ILC3-mediated antigen-presentation, interleukin-2 gradients, and α v integrin. Finally, single-cell analyses demonstrate that ILC3 and RORγt + Treg interactions are impaired in inflammatory bowel disease. Our results define a novel paradigm whereby ILC3s positively select for antigen specific RORγt + Tregs, and against Th17 cells, to establish immune tolerance to the microbiota and intestinal health.

Background: Delays in biologic or small molecule medication administration are associated with increased adverse events, hospitalization, and surgery in inflammatory bowel disease (IBD). We evaluated the impact of a quality improvement (QI) intervention on the time to administration of biologics or small molecules (TABS) in IBD. Methods: Data were retrospectively extracted for IBD patients prescribed biologics or small molecules from a convenience sample of providers participating in an accredited QI educational intervention (baseline cohort). Subsequent to the intervention, data were prospectively collected from patients prescribed these medications (postintervention cohort). Dates related to steps between a treatment decision to medication administration were collected. The primary outcome compared TABS in baseline and postintervention cohorts. Results: Eighteen physicians provided survey and patient data for 200 patients in each cohort (n=400). The median time to medication administration (TABS) decreased from baseline to postintervention cohorts (30 vs. 26 d, P=0.04). Emergency room visits before medication administration also decreased (25.5% vs. 12.5%, P=0.001). Similar numerical TABS reductions were observed in subgroups limited to physicians providing patients to both cohorts and for individual medications prescribed. Primary contributors to delays included filling prescriptions subsequent to insurance approval and dispensation subsequent to this. Conclusions: A QI intervention successfully reduced medication administration times (TABS) by accelerating provider-dependent steps. This intervention was associated with reduced emergency room visits. We propose TABS as a quality metric to assess the effective delivery of therapies in IBD. Further evaluation of QI interventions, patient education on prescription drug insurance, and quality metrics are warranted.

Abstract Background and Aims Therapeutic drug monitoring (TDM) with measurement of serum drug and antidrug antibody concentrations is used to optimize tumor necrosis factor antagonists (anti-TNF). The endoscopic healing index (EHI) is a validated serum-based assay to measure mucosal inflammation in adults with Crohn disease (CD). Our objectives were to evaluate the relationship between EHI and TDM results and to determine the anti-TNF concentration range associated with EHI <20 (consistent with endoscopic remission). Methods Adult and pediatric patients with CD (N = 1731) were selected retrospectively from a clinical laboratory cohort. Patients were selected if they had an ICD-10 code for CD and if results for EHI and TDM were available within 30 days of each other. The relationship between EHI and TDM results was examined and the anti-TNF concentration range associated with EHI <20 vs >50 was evaluated. Results Median anti-TNF concentration was higher in patients with EHI <20 vs >50 for infliximab (N = 796): 11.1 vs 3.4 µg/mL and for adalimumab (N = 935): 9.2 vs 5.0 µg/mL (P < 0.0001 both drugs). Patients with antibodies to infliximab (12.8%) or adalimumab (14.9%) had lower anti-TNF concentrations (P < 0.001 both drugs) and higher EHI (P < 0.01 both drugs). The concentration range for infliximab: 5–15 µg/mL (5–9 µg/mL in pediatric patients) and for adalimumab: 5–10 µg/mL (8 µg/mL in pediatric patients) best discriminated EHI <20 vs >50. Conclusions We report the anti-TNF concentration range associated with EHI <20. Combined testing of EHI and TDM is proposed as a noninvasive approach for treat-to-target management which could improve the ability to monitor disease and optimize anti-TNF therapy.

Bleeding and altered iron distribution occur in multiple gastrointestinal diseases, but the importance and regulation of these changes remain unclear. We found that hepcidin, the master regulator of systemic iron homeostasis, is required for tissue repair in the mouse intestine after experimental damage. This effect was independent of hepatocyte-derived hepcidin or systemic iron levels. Rather, we identified conventional dendritic cells (cDCs) as a source of hepcidin that is induced by microbial stimulation in mice, prominent in the inflamed intestine of humans, and essential for tissue repair. cDC-derived hepcidin acted on ferroportin-expressing phagocytes to promote local iron sequestration, which regulated the microbiota and consequently facilitated intestinal repair. Collectively, these results identify a pathway whereby cDC-derived hepcidin promotes mucosal healing in the intestine through means of nutritional immunity.

more precisely dose optimize IFX and improve therapeutic outcomes.As part of a single arm intervention study, we report the dosing forecasts, PK parameters and clinical outcomes from the real-world application of dashboard-guided proactive IFX optimization during induction in IBD.Methods: Patients received physician-selected doses of 5 mg/kg or 10 mg/kg at weeks 0 and 2. Weight (kg), albumin (ALB), C-reactive protein (CRP), and IFX dose from each infusion (INF) were entered into a PK dashboard (iDose™).Additionally, pre-dose IFX concentration and ATI presence from INF2 and INF3 were inputted.The cumulative data from each INF were used to inform timing of the subsequent INF Forecasts driven by adaptive Bayesian modeling were generated to maintain target serum concentrations for INF3 (17 µg/mL) and INF4 (10 µg/mL).Primary outcome was proportion of patients forecasted accelerated dosing (AD) intervals by INF3 (< 22 days) and or INF4 (< 49 days).Descriptive statistics summarized data as median and interquartile range [IQR] or frequency.Univariate analysis tested associations and compared outcomes of those who did or did not follow the forecasted interval.Results: Of the 180 patients (median age 14.7 years) enrolled, 53% initiated IFX 5 mg/kg and 47% 10 mg/kg (Table 1).Eleven patients stopped IFX due to ATI or non-response (n=7) or lost to follow up (n=4) before INF4.AD was forecasted for 41% and 69% of patients by INF3 and INF4, respectively, increasing to 80% if induced with 5 mg/kg (Figure 1).Younger age (p< 0.04) and lack of steroids (p=0.02) at baseline was associated AD by INF4.AD group had significantly shorter forecasted intervals vs. non AD group for INF 3 and INF4; 17 vs 30 days (p < 0.0001) and 33 vs. 59 days (p < 0. 0001), respectively.INF4 IFX level was lower for the AD group vs. non AD group (10.9 µg/mL vs. 15.4 µg/mL, p= 0.0002).Patient noncompliance with INF3 forecast (n=44) had a lower IFX level than those who followed (15.6 µg/mL vs 24.3 µg/mL, p =0.003)).Noncompliance with INF4 (n=38), resulted in lower IFX levels (6.9 µg/mL vs. 13.9 µg/mL, p < 0.0001), higher ATI rates (p < 0.002) and less CRP normalization (p=0.002).Conclusions: The use of PK dashboards to optimize IFX induction dosing is feasible in a real world setting and demonstrates that the majority of IBD patients require AD by INF4 regardless of mg/kg dosing and noncompliance is associated with 11 fold increase in ATI formation. Baseline Characteristics

Background: The incidence and prevalence of Inflammatory BowelDisease (IBD) in the U.S. is increasing. Because adequate sleep quality and duration play a role in the mental and physical wellbeingof children, this study aimed to determine the prevalence of sleep difficulties in our urban pediatric IBD cohort and evaluateassociations between sleep quality and disease severity. Methods: Patients completed the Pittsburgh Sleep Quality Index(PSQI) questionnaire during an office visit. Chart review provided demographic information, and Pediatric Crohn’s Disease ActivityIndex (PCDAI) and Pediatric Ulcerative Colitis Activity Index (PUCAI) scores were calculated from the day of the visit. Results: The prevalence of sleep problems was 33.54% (95%CI: 26.24% to 41.48%; p-value=0.02). PUCAI scores in children with sleep problems (PSQI mean 19.17 ± 20.43) were significantlyhigher than PUCAI scores in children without sleep problems. There was no association between total PSQI scores, classification of IBD,age, gender, ethnicity, steroid use, or disease duration. Conclusion: Our IBD cohort reported a 33% prevalence ofsleep disturbance symptoms. In the small group of patients withUlcerative Colitis (UC), there was a trend toward a greater degree ofsleep disturbances and a higher PUCAI score. Further investigationinto sleep disorders among children with IBD is warranted toprovide further insight into this issue. Additional evaluation of the differences between Crohn’s disease (CD) and ulcerative colitis asthey relate to sleep quality as well as studies implementing objectivesleep assessments, such as polysomnography or actigraphy, arewarranted as they may offer better understanding of the relationshipbetween pediatric IBD and sleep quality.

Objectives. The available literature on pulmonary disease in pediatric inflammatory bowel disease is limited. We evaluated the prevalence of pulmonary manifestations in pediatric inflammatory bowel disease and their association with disease severity. Methods. Patients completed the St. George’s Respiratory Questionnaire (SGRQ), a self-reported measure of quality of life in patients with pulmonary disease. Chart review provided demographic information and Pediatric Crohn’s Disease Activity Index (PCDAI) and Pediatric Ulcerative Colitis Activity Index scores. Regression models were utilized to evaluate associations between SGRQ score and clinical risk factors. Results. The prevalence of pulmonary manifestations was 9.62% (95% confidence interval = 5.48% to -15.36%). PCDAI scores in Crohn’s disease patients with pulmonary symptoms were significantly higher (SGRQ mean = 10.71 ± 10.94) than in patients without such symptoms. SGRQ score was also higher in patients with indeterminate colitis (8.64, 95% confidence interval = 0.72-16.57, P = .03), when compared with Crohn’s disease. Conclusions. Additional investigations including pulmonary function tests and imaging could provide further insight into this issue.

Interleukin (IL)-2 is a pleiotropic cytokine that is necessary to prevent chronic inflammation in the gastrointestinal tract1-4. The protective effects of IL-2 involve the generation, maintenance and function of regulatory T (Treg) cells4-8, and the use of low doses of IL-2 has emerged as a potential therapeutic strategy for patients with inflammatory bowel disease9. However, the cellular and molecular pathways that control the production of IL-2 in the context of intestinal health are undefined. Here we show, in a mouse model, that IL-2 is acutely required to maintain Treg cells and immunological homeostasis throughout the gastrointestinal tract. Notably, lineage-specific deletion of IL-2 in T cells did not reduce Treg cells in the small intestine. Unbiased analyses revealed that, in the small intestine, group-3 innate lymphoid cells (ILC3s) are the dominant cellular source of IL-2, which is induced selectively by IL-1β. Macrophages in the small intestine produce IL-1β, and activation of this pathway involves MYD88- and NOD2-dependent sensing of the microbiota. Our loss-of-function studies show that ILC3-derived IL-2 is essential for maintaining Treg cells, immunological homeostasis and oral tolerance to dietary antigens in the small intestine. Furthermore, production of IL-2 by ILC3s was significantly reduced in the small intestine of patients with Crohn's disease, and this correlated with lower frequencies of Treg cells. Our results reveal a previously unappreciated pathway in which a microbiota- and IL-1β-dependent axis promotes the production of IL-2 by ILC3s to orchestrate immune regulation in the intestine.

The primary aim of this Clinical Report by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition is to provide formal guidance to pediatric gastroenterologists and clinicians, health systems, and insurance payers regarding home- and office-based infusions for biologic therapies in pediatric inflammatory bowel disease. Patients in North America are increasingly denied coverage by payers based on "place of service" codes at hospital-based infusion units where the treating clinicians primarily provide care. A task force with topic expertise generated 8 best practice recommendations to ensure quality of care for pediatric patients with inflammatory bowel disease receiving non-hospital-based biologic infusions. Pragmatic considerations discussed in this report include patient safety, pediatric-trained nurse availability, care coordination, patient-centeredness, shared liability, administrative support, clinical governance, and costs of care.

The risk of venous thromboembolism (VTE) is significantly increased in patients with inflammatory bowel disease (IBD). For the adult population, prophylaxis guidelines exist to help guide physicians in their management of high-risk IBD patients. Although it is known that children with IBD also experience increased rates of VTE, there is no clear consensus on how best to prevent these unwanted complications. We sought to better understand practicing pediatric gastroenterologists' awareness of this issue and practices surrounding prevention of VTE in their pediatric patients. We found that pediatric gastroenterologists are well aware of the increased risk for VTE in children with IBD, that anticoagulant prophylaxis is infrequently used for pediatric patients, and that the most commonly cited reason for not providing prophylaxis is the lack of available guidelines in the literature.

An 18-month-old male presented to an outside hospital following multiple episodes of bilious emesis. Three days prior, the patient reportedly ingested 2 Buckyball magnets. At the outside hospital, an abdominal radiograph showed 2 magnets in the mid-to-lower abdomen with evidence of a small bowel obstruction. The patient was transferred to our institution for management. On arrival in our emergency department, the patient’s vitals were temperature 37.1°C, heart rate 135 beats/ min, blood pressure 103/68 mm Hg. Physical examination was unremarkable. Laboratory analysis was significant for white blood cell count of 8.1 × 10/μL, blood urea nitrogen 30 mg/dL, hemoglobin 11.7 g/dL, and anion gap of 20. Repeat abdominal radiograph showed 2 round radiopaque objects in the mid-lower abdomen as well as a small bowel obstruction with a transition point at the site of the radiopaque foreign bodies but no evidence of free air (Figure 1). The patient was taken emergently to the operating room for exploratory laparotomy and removal of foreign bodies. A perforated terminal ileum was found where the magnets were located as well as a near-perforated jejunum and intra-abdominal abscess (Figure 2). Abdominal fluid cultures grew Gram-negative rods and he was subsequently treated with piperacillin/tazobactam.

Nearly one-quarter of patients with inflammatory bowel disease (IBD) are younger than 20 years of age at diagnosis. Furthermore, the incidence of IBD in children continues to increase. Nevertheless, variation in management exists within the care of patients with IBD with regards to disease screening and preventive care. A multidisciplinary approach that involves the general practitioner and pediatric gastroenterologist is needed to routinely monitor growth, bone health, vitamin and mineral deficiencies, vaccination status, and endoscopic surveillance. It is also important to monitor for extraintestinal manifestations of IBD that may affect the liver, joints, skin, and eyes. The purpose of this article is to provide an updated overview of comprehensive care for pediatric patients with IBD.