Lower intestinal barrier function is associated with increased risk for development of Crohn’s disease
More greenspace associated with lower rates of development of IBD
Exome sequencing has shown ~3% of pIBD with genetic mutations linked to monogenetic IBD & 1% with mutations which could benefit from HSCT. Identifying specific defects may lead to other treatments as well (eg. Leflunomide for TTC7A deficiency). Related blog posts:
A recent retrospective study (JR Kelsen et al. Inflamm Bowel Dis 2020; 26: 909-18) compares children diagnosed with inflammatory bowel disease at different age points and their outcomes. During a 9 year study span (2008-16), there were 229 subjects diagnosed as very-early onset (<6 years, VEO), 221 diagnosed as intermediate onset (6-10 years), and 521 diagnosed as older onset (> 10 years)
VEO-IBD patients were significantly more likely to have had a diverting ileostomy and colectomy than the older patients. Diverting ileostomy rates: 12.2%, 4.1%, and 1.2% respectively. Colectomy rates: 7.4%, 4.1%, and 1.7% respectively.
Ileocecal resections were significantly higher in the older-onset IBD population. In the older group, these resections were noted in 64/521 (12.2%) compared to 1/229 (0.4%) in the VEO group and 10/221 (4.5%) in the intermediate group.
VEO-IBD patients had higher medication failure rates at 1 year into treatment and were more frequently readmitted to the hospital. For infliximab (IFX), failure rates were 62.4% for VEO subjects compared to 14.6% for older-onset subjects. For adalimumab, the respective rates were 53.2% vs. 7.2%.
Targeted therapy was successfully used almost exclusively in the VEO-IBD population
My take: Children with VEO-IBD have a more severe disease course than older children. Since monogenetic disorders occur in ~8% of the VEO population, targeted therapies are more likely; however; ~2% of older children also have a monogenetic disorder and as such, targeted therapy could be important in this group as well.
While the article makes numerous useful points, explicit recommendations are not clearly stated.
Epidemiology: 6-15% of pediatric IBD population presents at <6 years of age
Children with VEO-IBD need careful immunologic evaluation. Some of the specific disorders that need to be considered include Chronic Granulomatous Disease (can check DHR) and XIAP (can check a flow cytometry-based assay).
Besides panendoscopy, the article recommends close collaboration with the pathologist to identify specific features of the numerous VEO-IBD disorders (most listed/described in Table 1)
Identification of VEO-IBD disorders with genetic testing (either whole exome or targeted gene panel) helps determine specific medical therapies and/or stem cell transplantation for disorders like CTLA4B deficiency, LRBA defects, IL-10 deficiency, XIAP, STXBP2, and FOXP3 deficiency.
Infliximab does not work as well in VEO-IBD patients. A recent study found only 12% remained on infliximab 3 years after initiation.
VEO-IBD were much more likely to need surgery with rates of 50% for those with onset before 1 year and ~30% for those after 1 year of age. Colectomy should be considered with caution due to the overlapping presentation of Crohn’s disease and ulcerative colitis in this age group.
One topic that was not discussed was the potential role for dietary therapy in this age group.
S Olivia et al (including Stanley Cohen from GI Care for Kids) Clin Gastroenterol Hepatol 2019; 17: 2060-7. “A Treat to Target Strategy Using Panenteric Capsule Endoscopy in Pediatric Patients with Crohn’s Disease” In this prospective study with 48 children with Crohn’s disease, pan-enteric capsule endoscopy (PCE) detected inflammation in 34 (71%) at baseline, 22 (46%) at week 24, and 18 (39%) at week 52. PCE results were used to manage treatment and resulted in change in therapy in 71% at baseline and 23% at week 24. Furthermore, PCE increased the proportions of patients in deep remission, up to 58% at week 52.
M Wright, et al. J Pediatr 2019; 210: 220-5. This case report of a 4 year-old boy with a perianal abscess and granulomatous colitis identified a NCF4 mutation causing severe neutrophil dysfunction. He developed osteomyelitis with anti-TNF therapy and did not respond to vedolizumab. He had an excellent outcome following a hematopoietic stem cell transplantation. This study reinforces the potential benefit of investigating VEO-IBD which could allow more targeted therapy. Related blog post: Patterns and Puzzles with Very Early Onset Inflammatory Bowel Disease
P Zapater et al. Inflamm Bowel Dis 2019; 25: 1357-66. This study with 112 patients with Crohn’s disease showed that serum interleukin-10 levels were directly related to infliximab and adalimumab levels. This suggests that serum anti-TNF levels are significantly influenced by immunological activation.
JE Axelrad et al. Clin Gastroenterol Hepatol 2019; 17: 1311-22. This study, using the Swedish National Patient Register, showed that gastrointestinal infection increased the odds of developing IBD in a nationwide case-control study. “Of the patients with IBD, 3105 (7%) had a record of previous gastroenteritis compared with 17,685 control subjects (4.1%). IBD cases had higher odds for an antecedent episode of gastrointestinal infection (aOR 1.64), bacterial gastrointestinal infection (aOR 2.02) and viral gastrointestinal infection (aOR 1.55)…a previous episode of gastroenteriitis remained associated with odds for IBD more than 10 years later (aOR 1.26).” The authors note that they cannot formally exclude misclassification bias, but it appears that enteric infections contribute to the development of IBD in susceptible individuals.
With more widespread use of whole-exome sequencing (WES), the ability to study the genetic basis for rare disorders like very early onset inflammatory bowel disease (VEO-IBD) has improved considerably. A recent study (JR Kelsen et al. Gastroenterol 2015; 149: 1415-24) analyzed 125 patients (3 weeks to 4 years of age) and compared with pediatric IBD patients (n=45), adult-onset Crohn’s (n=20), and healthy controls (n=145). Link to abstract and online material. (Link includes full-text as well).
The authors focused their study on 400 genes/regions associated with primary immunodeficiency.
“Our analysis showed novel and rare variants within these genes that could contribute to the development of VEO-IBD, including rare heterozygous missense variants in IL10RA and previously unidentified variants in MSH5 and CD19.”
In their discussion, the authors elaborate on these findings. In addition, in Table 3, the authors elaborate on potential immunologic studies for these children.
Take home message: The authors recommend “a more complete immunologic evaluation be performed in patients with VEO-IBD.” Ultimately, understanding the complex genetics will lead to more individualized and successful treatments.