TNFSF13 insufficiency disrupts human colonic epithelial cell-mediated B cell differentiation.

Cytokines mediating epithelial and immune cell interactions modulate mucosal healing-a process that goes awry with chronic inflammation as in inflammatory bowel disease. TNFSF13 is a cytokine important for B cell maturation and function, but roles for epithelial TNFSF13 and putative contribution to inflammatory bowel disease are poorly understood. We evaluated functional consequences of a novel monoallelic TNFSF13 variant using biopsies, tissue-derived colonoids and induced pluripotent stem cell (iPSC)-derived colon organoids. TNFSF13 variant colonoids exhibited a >50% reduction in secreted TNFSF13, increased epithelial proliferation, and reduced apoptosis, which was confirmed in iPSC-derived colon organoids. Single cell RNA-sequencing, flow cytometry, and co-immunoprecipitation identified FAS as the predominant colonic epithelial receptor for TNFSF13. Imaging mass cytometry revealed an increase in epithelial-associated B cells in TNFSF13 variant colon tissue sections. Finally, TNFSF13 variant colonoids co-cultured with memory B cells demonstrated a reduction in the production of IgA+ plasma cells compared to control colonoid co-cultures. Our findings support a role for epithelial TNFSF13 as a regulator of colonic epithelial growth and epithelial crosstalk with B cells. SUMMARY: Epithelial TNFSF13 regulates colonic epithelial growth and epithelial-B cell interactions.

Serum cytokine panels in pediatric clinical practice.

BACKGROUND: Cytokines are soluble signaling proteins that regulate inflammation and coordinate immune responses. Serum cytokine panels are increasingly used in medical practice, yet our understanding of cytokines as biomarkers for disease remains limited. OBJECTIVE: We sought to analyze real-world single-center use of a multiplexed cytokine panel, correlate its results with diagnosis and severity, and explore its use in pediatric practice. METHODS: A multiplexed cytokine panel, able to return same-day results, was implemented in April 2020 at the Children's Hospital of Philadelphia (Philadelphia, Pa) and its performance was validated for clinical use. Coded patient data were collected using the REDCap database, and correlations between cytokine levels and outcomes of interest were analyzed retrospectively. RESULTS: Cytokine levels correlate with acuity of care, with patients admitted to the pediatric intensive care unit having the highest cytokine values. Patients with familial hemophagocytic lymphohistiocytosis (fHLH) showed prominent peaks in IFN-γ, IL-10, and TNF, whereas patients with sepsis exhibited high IL-6 and IL-8 with relatively modest IFN-γ. Cytokine release syndrome (CRS) after chimeric antigen receptor T-cell therapy often demonstrated pan-panel positivity at peak levels, with a similar pattern as that of fHLH. A ratio of [IFN-γ] + [IL-10]/[IL-6] + [IL-8] levels was able to distinguish fHLH and CRS from severe sepsis. CONCLUSIONS: Cytokine levels correlate with severity of illness and can help differentiate between syndromes that present similarly, including fHLH and CRS compared with sepsis. Cytokine panels can be used as biomarkers to inform diagnosis and management decisions, but significant work remains to dissect complex clinical patterns of disease.

The intestinal microbiome of inflammatory bowel disease across the pediatric age range.

Dysbiosis is associated with pediatric and adult-onset inflammatory bowel disease (IBD), but the role of dysbiosis and the microbiome in very early onset IBD (VEO-IBD) has not yet been described. Here, we aimed to demonstrate the impact of age and inflammation on microbial community structure using shotgun metagenomic sequencing in children with VEO-IBD, pediatric-onset IBD, and age-matched pediatric healthy controls (HC) observed longitudinally over the course of 8 weeks. We found disease-related differences in alpha and beta diversity between HC and children with IBD or VEO-IBD. Using a healthy microbial maturity index modeled from HC across the age range to characterize their gut microbiota, we found that children with pediatric-onset IBD and VEO-IBD had lower maturity than their age-matched HC groups, suggesting a disease effect on the microbial community. In addition, patients with pediatric IBD had significantly lower maturity than those with VEO-IBD, who had more heterogeneity at the youngest ages, highlighting differences in these two cohorts that were not captured in standard comparisons of alpha and beta diversity. These results demonstrate that young age and inflammation independently impact microbial community structure. However, the effect is not additive in the youngest patients, likely because of the heterogeneous and dynamic stool microbiome in this population.

Canakinumab for the treatment of autoinflammatory very early onset- inflammatory bowel disease.

Introduction: Therapeutic options are critically needed for children with refractory very early onset inflammatory bowel disease (VEO-IBD). Our aim was to evaluate clinical response to canakinumab, an anti-IL-1ß monoclonal antibody, in patients with VEO-IBD whose phenotype resembles those with monogenic autoinflammatory disease. Methods: This is a single center retrospective study of patients with VEO-IBD with autoinflammatory phenotype (AIP) in the absence of identified monogenic disease treated with canakinumab for >6 months. AIP was defined as confirmed IBD with associated signs of systemic inflammation in the absence of infection, including leukocytosis, markedly elevated inflammatory markers, and extraintestinal manifestations (recurrent fevers, oral ulcers, arthritis). Primary outcomes included clinical response in disease activity indices after 6 months of therapy. Secondary outcomes included rate of AIP signs and symptoms, growth, surgery, steroid use, hospitalizations, and adverse events. Results: Nineteen patients were included: 47% with infantile onset, 58% classified as IBD-U, and 42% classified as CD. At baseline, 37% were biologic naïve, and canakinumab was used as dual therapy in 74% of patients. Clinical response was achieved in 89% with statistically significant improvement in PCDAI and PUCAI. Clinical remission was achieved in 32% of patients. There was significant improvement in the clinical manifestations of AIP and the biochemical markers of disease. Number of hospitalizations (p<0.01) and length of stay (p<0.05) decreased. Growth improved with median weight-for-length Z-score increasing from -1.01 to 1.1 in children less than 2 years old. There were minimal adverse events identified during the study period. Conclusion: Canakinumab may be an effective and safe treatment for a subset of children with VEO-IBD with AIP, as well as older patients with IBD. This study highlights the importance of a precision medicine approach in children with VEO-IBD.

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.

Clostridioides difficile Infection in Pediatric Inflammatory Bowel Disease: A Clinician's Dilemma.

Clostridioides difficile infection (CDI) in children with inflammatory bowel disease (IBD) can present and manifest differently from the general population with CDI, and it can worsen the underlying disease course. Furthermore, current clinical assays used to test for CDI do not accurately distinguish between true CDI or colonization. This uncertainty leads to difficulty in identifying the etiology and therapy for symptomatic patients with IBD. Improved diagnostic tests, biomarkers, and safe and effective treatment options are greatly needed for this vulnerable population.

Bowel-associated dermatosis-arthritis syndrome in a child with very early onset inflammatory bowel disease.

A 6-year-old boy with severe very early-onset inflammatory bowel disease (VEO-IBD) was admitted for 1 week of high fevers, loose stools, joint pains, and myalgias. He subsequently developed a progressive, papular, and vesiculopustular eruption on his face with rapid spread to his trunk and extremities. Histopathology demonstrated dense dermal neutrophilic inflammation. Findings were consistent with bowel-associated dermatosis-arthritis syndrome (BADAS), which is rarely reported in children and requires further characterization.

Colonoids From Patients With Pediatric Inflammatory Bowel Disease Exhibit Decreased Growth Associated With Inflammation Severity and Durable Upregulation of Antigen Presentation Genes.

BACKGROUND: Defining epithelial cell contributions to inflammatory bowel disease (IBD) is essential for the development of much needed therapies for barrier repair. Children with very early onset (VEO)-IBD have more extensive, severe, and refractory disease than older children and adults with IBD and, in some cases, have defective barrier function. We therefore evaluated functional and transcriptomic differences between pediatric IBD (VEO and older onset) and non-IBD epithelium using 3-dimensional, biopsy-derived organoids. METHODS: We measured growth efficiency relative to histopathological and clinical parameters in patient enteroid (ileum) and colonoid (colon) lines. We performed RNA-sequencing on patient colonoids and subsequent flow cytometry after multiple passages to evaluate changes that persisted in culture. RESULTS: Enteroids and colonoids from pediatric patients with IBD exhibited decreased growth associated with histological inflammation compared with non-IBD controls. We observed increased LYZ expression in colonoids from pediatric IBD patients, which has been reported previously in adult patients with IBD. We also observed upregulation of antigen presentation genes HLA-DRB1 and HLA-DRA, which persisted after prolonged passaging in patients with pediatric IBD. CONCLUSIONS: We present the first functional evaluation of enteroids and colonoids from patients with VEO-IBD and older onset pediatric IBD, a subset of which exhibits poor growth. Enhanced, persistent epithelial antigen presentation gene expression in patient colonoids supports the notion that epithelial cell-intrinsic differences may contribute to IBD pathogenesis.

The Treatment of Pediatric Inflammatory Bowel Disease with Biologic Therapies.

PURPOSE OF REVIEW: Biologics for the treatment of inflammatory bowel disease (IBD) have been transformative to the therapeutic goals in the pediatric population. We review the biologics used to treat IBD, highlighting the importance of patient selection, dosing considerations, and therapeutic drug monitoring in children. RECENT FINDINGS: Infliximab is well-established as a safe and efficacious therapy for Crohn's disease and ulcerative colitis. Both dose escalation strategies and therapeutic drug monitoring increase the likelihood of response to anti-TNFα therapies. Early real-world experience of vedolizumab and ustekinumab in pediatric IBD shows promising results, including clinical response rates comparable to what is seen in adults, but there are limited data using them as first-line therapies. Biologic therapies have improved outcomes in pediatric IBD, including achieving mucosal healing as well as improved growth and pubertal development. Therapeutic drug monitoring improves likelihood of response to anti-TNFα therapies, but further studies for vedolizumab and ustekinumab are necessary.

Dynamics of the Stool Virome in Very Early-Onset Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Dysbiosis of the gut microbiota is a well-known correlate of the pathogenesis of inflammatory bowel disease [IBD]. However, few studies have examined the microbiome in very early-onset [VEO] IBD, which is defined as onset of IBD before 6 years of age. Here we focus on the viral portion of the microbiome-the virome-to assess possible viral associations with disease processes, reasoning that any viruses potentially associated with IBD might grow more robustly in younger subjects, and so be more detectable. METHODS: Virus-like particles [VLPs] were purified from stool samples collected from patients with VEO-IBD [n = 54] and healthy controls [n = 23], and characterized by DNA and RNA sequencing and VLP particle counts. RESULTS: The total number of VLPs was not significantly different between VEO-IBD and healthy controls. For bacterial viruses, the VEO-IBD subjects were found to have a higher ratio of Caudovirales vs to Microviridae compared to healthy controls. An increase in Caudovirales was also associated with immunosuppressive therapy. For viruses infecting human cells, Anelloviridae showed higher prevalence in VEO-IBD compared to healthy controls. Within the VEO-IBD group, higher levels of Anelloviridae DNA were also positively associated with immunosuppressive treatment. To search for new viruses, short sequences enriched in VEO-IBD samples were identified, and some could be validated in an independent cohort, although none was clearly viral; this provides sequence tags to interrogate in future studies. CONCLUSIONS: These data thus document perturbations to normal viral populations associated with VEO-IBD, and provide a biomarker-Anelloviridae DNA levels-potentially useful for reporting the effectiveness of immunosuppression.

Positioning Biologic Therapies in the Management of Pediatric Inflammatory Bowel Disease.

The incidence and prevalence of pediatric inflammatory bowel disease (IBD) are rising worldwide, with a steep increase in children under 5 years of age. Compared to adult IBD, pediatric IBD presents with a more severe, aggressive phenotype and unique complications, notably growth impairment. Treatment goals include achieving intestinal healing, reaching growth potential, and optimizing quality of life, all while limiting drug toxicities. In the last 2 decades, the advent of anti-tumor necrosis factor (TNF) α agents has significantly increased the potential to reach these goals. However, nonresponse or loss of response to anti- TNFα agents is still encountered in approximately one-third of patients. Although the development of novel biologic therapies has offered new alternatives in recent years, the use of these therapies in the pediatric setting has been limited due to delayed approval. This article summarizes the key evidence for biologic agents currently used in the treatment of pediatric IBD and discusses challenges and barriers unique to pediatric drug development.

The Unique Disease Course of Children with Very Early onset-Inflammatory Bowel Disease.

BACKGROUND: Insight into the pathogenesis of very early onset-inflammatory bowel disease (VEO-IBD) has expanded through the identification of causative monogenic defects detected in a subset of patients. However, the clinical course of this population remains uncertain. The study objective is to determine whether VEO-IBD is associated with more severe disease, defined as increased surgical intervention and growth failure, than older pediatric IBD. Secondary outcomes included therapeutic response and hospitalizations. METHODS: Subjects with IBD diagnosed younger than 6 years old (VEO-IBD) were compared with children diagnosed 6 to 10 (intermediate-onset) and older than 10 years of age (older-onset IBD). Metadata obtained from the medical record included age of onset, disease phenotype and location, surgeries, medical therapy, and comorbid conditions. Length of follow-up was at least 1 year from diagnosis. RESULTS: There were 229, 221, and 521 subjects with VEO, intermediate-onset, and older-onset IBD, respectively. Very early onset-inflammatory bowel disease subjects underwent more diverting ileostomies (P < 0.001) and colectomies (P < 0.001) than the older children. There was less improvement in weight- and height-for-age Z scores during the follow-up period in subjects with VEO-IBD. Additionally, subjects with VEO-IBD had higher rates of medication failure at 1 year and were more frequently readmitted to the hospital. Targeted therapy was successfully used almost exclusively in VEO-IBD. CONCLUSION: Patients with VEO-IBD can have a more severe disease course with increased surgical interventions and poor growth as compared with older-onset IBD patients. Further, VEO-IBD patients are more likely to be refractory to conventional therapies. Strategies using targeted therapy in these children can improve outcome and, in some cases, be curative.

Genomic and Immunologic Drivers of Very Early-Onset Inflammatory Bowel Disease.

PURPOSE OF REVIEW: Inflammatory bowel disease (IBD) is a multifactorial disease caused by dysregulated immune responses to commensal or pathogenic intestinal microbes, resulting in chronic intestinal inflammation. However, a subset of patients with IBD diagnosed <6 years of age, known as very early-onset (VEO)-IBD, can be phenotypically and genetically distinct from older onset IBD. We aim to review the clinical presentation of children with VEO-IBD and recent discoveries that point to the underlying genomic and immunologic drivers of disease, and the significant impact on our therapeutic decisions. RECENT FINDINGS: VEO-IBD is increasing in incidence and is associated with more severe disease, aggressive progression, and poor response to most conventional therapies. This article will review some of the genetic findings in this population and the subsequent impact on therapy, with targeted approaches. SUMMARY: Children with VEO-IBD may present with a different phenotype and more severe disease than older children and adults. An integrated approach combining genetics, immunology, and traditional IBD evaluations can lead to the identification of causal defects that directly impact management. These strategies can also be employed in older onset refractory IBD.

Distinct Histopathological Features at Diagnosis of Very Early Onset Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Children with very early onset inflammatory bowel disease [VEO-IBD] represent a unique cohort, often with a severe phenotype that is refractory to conventional medications, and some cases have underlying primary immunodeficiencies. Previous work has identified distinct histopathological patterns in the gastrointestinal tract in patients with primary immunodeficiencies. The aim of this study is to characterise the diagnostic histological findings in patients with VEO-IBD as compared with older onset paediatric IBD, and determine if there are unique pathological changes that can shed light on the driving forces of the disease, particularly immunodeficiencies. METHODS: Clinical retrospective chart review, including disease characteristics and endoscopic findings, was performed on all included subjects. Two paediatric pathologists reviewed biopsies from diagnostic upper endoscopies and colonoscopies of subjects with very early onset inflammatory bowel disease and older onset inflammatory bowel disease, to evaluate for the presence of 11 histological features previously associated with inflammatory bowel disease and primary immunodeficiencies. RESULTS: The diagnostic gastrointestinal biopsies of subjects with very early onset inflammatory bowel disease differed from those in older onset paediatric IBD, demonstrated by increased frequency of apoptosis, severe chronic architectural changes, small intestine villous blunting, and eosinophils in the crypts, lamina propria, and surface epithelium. CONCLUSIONS: The diagnostic biopsies of children with very early onset inflammatory bowel disease can identify characteristic features that may be important in guiding the diagnostic work-up in this population.

Novel ZBTB24 Mutation Associated with Immunodeficiency, Centromere Instability, and Facial Anomalies Type-2 Syndrome Identified in a Patient with Very Early Onset Inflammatory Bowel Disease.

BACKGROUND: Very early onset inflammatory bowel disease, diagnosed in children ≤5 years old, can be the initial presentation of some primary immunodeficiencies. METHODS: In this study, we describe a 17-month-old boy with recurrent infections, growth failure, facial anomalies, and inflammatory bowel disease. Immune evaluation, whole-exome sequencing, karyotyping, and methylation array were performed to evaluate the child's constellation of symptoms and examination findings. RESULTS: Whole-exome sequencing revealed that the child was homozygous for a novel variant in ZBTB24, the gene associated with immunodeficiency, centromere instability, and facial anomalies type-2 syndrome. CONCLUSION: This describes the first case of inflammatory bowel disease associated with immunodeficiency, centromere instability, and facial anomalies type-2 syndrome in a child with a novel disease-causing mutation in ZBTB24 found on whole-exome sequencing.

Endoscopic ultrasound with or without fine-needle aspiration has a meaningful impact on clinical care in the pediatric population.

BACKGROUND AND OBJECTIVES: The safety and utility of endoscopic ultrasound (EUS) for the evaluation and management of gastrointestinal (GI) tract disorders among adults has been established. The literature on safety and efficacy in a pediatric referral population (under 21 years of age) is limited. We hypothesized that EUS is safe and useful in the pediatric population. We reviewed the pediatric EUS experience at a single tertiary-care system. We describe the indications, findings, safety, technical success rate, and impact on clinical outcomes. PATIENTS AND METHODS: All patients 21 years of age or younger referred for EUS between 5, 2007 and 11, 2012 were identified from our electronic medical record databases. Retrospective chart review was then conducted to document demographics, procedure indications, procedure type (diagnostic or therapeutic), type of anesthesia used, EUS findings, and the clinical impact of EUS on the subsequent management of the patients. RESULTS: Seventy EUS procedures were attempted in 58 patients during the study. Of these, two EUS procedures were aborted due to inadequate moderate sedation and 68 were successfully completed. The median age at initial endoscopy was 18 years (range 6-21 years), 50% were male and 65% were Caucasian. Four patients underwent EUS-guided pseudocyst drainage. Among the remaining 54 patients, the indications for EUS were the evaluation of GI mucosal/submucosal lesions (n = 14), acute or recurrent pancreatitis (n = 10), localization of suspected insulinoma (n = 8), evaluation of pancreatic abnormalities seen on prior imaging (n = 6), surveillance of tumors or evaluation of luminal lesions in hereditary syndromes (n = 6), abdominal pain of suspected pancreatobiliary origin (n = 5), and other rare indications (n = 5). Fine-needle aspiration was performed in 13 (9 diagnostic, 4 therapeutic) and trans-gastric fine-needle contrast injection of the pancreatic duct was performed in one patient without any complications. Sedation (data available for 66 procedures) included general endotracheal anesthesia in 38 (57%), monitored anesthesia care (MAC) in 19 (29%), and moderate sedation in 9 (14%). There were 4 minor intra-procedural anesthesia-related complications (laryngospasm in 2 and hypoxemia from airway obstruction and secretions in 2) in MAC and general endotracheal anesthesia (GA) cases, and 1 postprocedural complication (fever after pseudocyst drainage). EUS can achieve the diagnostic or therapeutic goal and ruled out suspected pathology in 88% of cases precluding need for additional testing. CONCLUSIONS: (1) EUS in the pediatric population is technically successful and efficacious. (2) Therapeutic and diagnostic EUS impacted clinical care decisions. (3) There is a low risk of immediate significant complications. (4) The overall efficacy and safety support the performance of EUS in a pediatric population by experienced endoscopists.

Pediatric Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), including Crohn disease, ulcerative colitis, and IBD-unspecified, is a chronic immune-mediated condition of the gastrointestinal tract in which the goal of treatment is to induce and maintain durable remission. In pediatrics, there is a wide spectrum of presenting symptoms, but esophagogastroduodenoscopy and colonoscopy are imperative to confirming the diagnosis. Treatment goals include achieving mucosal healing of the gastrointestinal tract, reaching growth potential, limiting medication toxicities, and optimizing quality of life for all patients.