Mamoun Elawad

Infant colitis—it's in the genes

Department of Immunology, Division of Infection and Immunity, University College London, Royal Free Hospital, London, UK (E-O Glocker MD, M Perro MSc, Prof B Grimbacher MD); Department of Haematology, University Hospital Freiburg, Freiburg, Germany (N Frede); Department of Paediatric Laboratory Medicine (Prof N Sebire MD) and Department of Paediatric Gastroenterology (M Elawad MD, N Shah MD), Great Ormond Street Hospital, University College London, London, UK

Clinical outcome in IL-10-and IL-10 receptor-deficient patients with or without hematopoietic stem cell transplantation

BACKGROUND Inherited deficiencies of IL-10 or IL-10 receptor (IL-10R) lead to immune dysregulation with life-threatening early-onset enterocolitis. OBJECTIVES We sought to gather clinical data of IL-10/IL-10R-deficient patients and devise guidelines for diagnosis and management, including hematopoietic stem cell transplantation (HSCT). METHODS We enrolled 40 patients with early-onset enterocolitis and screened for mutations in IL10/IL10R using genetic studies, functional studies, or both of the IL-10 signaling pathway. Medical records of IL-10/IL-10R-deficient patients were reviewed and compiled. RESULTS Of 40 patients, we identified 7 with novel mutations, predominantly in consanguineous families with more than 1 affected member. IL-10/IL-10R-deficient patients had intractable enterocolitis, perianal disease, and fistula formation. HSCT was carried out in 2 patients with IL-10 deficiency and 1 patient with IL-10R α chain deficiency and proved to be an effective therapy, leading to rapid improvement of clinical symptoms and quality of life. CONCLUSION Because the defect in patients with IL-10/IL-10R deficiency resides in hematopoietic lineage cells and their colitis is resistant to standard immunosuppressive therapy, HSCT should be considered early as a potentially curative therapeutic option.

Interleukin-10 and Interleukin-10–Receptor Defects in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease characterized by abdominal pain, bloody diarrhoea, and malabsorption leading to weight loss. It is considered the result of inadequate control of an excessive reaction of the immune system to the resident flora of the gut. Like other primary immunodeficiencies, IL-10 and IL-10 receptor (IL10R) deficiency present with IBD and demonstrate the sensitivity of the intestine to any changes of the immune system. Both IL-10 and IL10R deficiency cause severe early-onset enterocolitis and can be successfully treated by hematopoietic stem cell transplantation (HSCT).

Targeted gene panel sequencing in children with very early onset inflammatory bowel disease—evaluation and prospective analysis

Background Multiple monogenetic conditions with partially overlapping phenotypes can present with inflammatory bowel disease (IBD)-like intestinal inflammation. With novel genotype-specific therapies emerging, establishing a molecular diagnosis is becoming increasingly important. Design We have introduced targeted next-generation sequencing (NGS) technology as a prospective screening tool in children with very early onset IBD (VEOIBD). We evaluated the coverage of 40 VEOIBD genes in two separate cohorts undergoing targeted gene panel sequencing (TGPS) (n=25) and whole exome sequencing (WES) (n=20). Results TGPS revealed causative mutations in four genes (IL10RA, EPCAM, TTC37 and SKIV2L) discovered unexpected phenotypes and directly influenced clinical decision making by supporting as well as avoiding haematopoietic stem cell transplantation. TGPS resulted in significantly higher median coverage when compared with WES, fewer coverage deficiencies and improved variant detection across established VEOIBD genes. Conclusions Excluding or confirming known VEOIBD genotypes should be considered early in the disease course in all cases of therapy-refractory VEOIBD, as it can have a direct impact on patient management. To combine both described NGS technologies would compensate for the limitations of WES for disease-specific application while offering the opportunity for novel gene discovery in the research setting.

Phenotypic Characterization of Very Early-onset IBD Due to Mutations in the IL10, IL10 Receptor Alpha or Beta Gene: A Survey of the GENIUS Working Group.

Objective:Early-onset inflammatory bowel disease starting within the first months of life could be due to a particular genetic defect. We set up the GENetically determined ImmUne-mediated enteropathieS (GENIUS) network and collected infants with a proven defect of the IL10 axis for accurate phenotyping of disease presentation and evolution. Design:Ten patients with early-onset inflammatory bowel disease with confirmed mutations in IL10, IL10RA, or IL10RB genes were characterized on clinical, endoscopic–histological, immunobiological, and radiological findings. Functional assays to confirm defective responses to IL10 were performed on peripheral blood mononuclear cells. Results:A functional defect in IL10 signaling was confirmed in all IL10R patients tested. Disease started with severe diarrhea within the first 12 weeks in all patients. All infants showed Crohns disease–like ulcerations limited to the colon with marked perianal inflammation (fissures, abscess, and fistula); disease progression to the small bowel occurred in only 1 patient. Four of the 10 patients had granulomata on histology, and all patients showed Crohns disease–like mesenteric infiltration on imaging. Disease pattern was indistinguishable between IL10R alpha or beta chain or IL10 defects; autoimmunity was not observed. Mutations in IL10 were more frequently associated with bacterial and viral infections. Patients responded partially to treatment with steroids or anti–tumor necrosis factor drugs, whereas hematopoietic stem cell transplantation proved efficacious. Conclusion:The importance of the IL10 pathway within the colonic mucosa is highlighted by the development of severe colitis within a few weeks in infants with mutations in IL10, IL10RA, or IL10RB. Immunosuppression failed to correct the defect in this pathway, which seems to be a key to controlling inflammation in the colon.

Clostridium difficile Modulates Host Innate Immunity via Toxin-Independent and Dependent Mechanism(s)

Clostridium difficile infection (CDI) is the leading cause of hospital and community-acquired antibiotic-associated diarrhoea and currently represents a significant health burden. Although the role and contribution of C. difficile toxins to disease pathogenesis is being increasingly understood, at present other facets of C. difficile-host interactions, in particular, bacterial-driven effects on host immunity remain less studied. Using an ex-vivo model of infection, we report that the human gastrointestinal mucosa elicits a rapid and significant cytokine response to C. difficile. Marked increase in IFN-γ with modest increase in IL-22 and IL-17A was noted. Significant increase in IL-8 suggested potential for neutrophil influx while presence of IL-12, IL-23, IL-1β and IL-6 was indicative of a cytokine milieu that may modulate subsequent T cell immunity. Majority of C. difficile-driven effects on murine bone-marrow-derived dendritic cell (BMDC) activation were toxin-independent; the toxins were however responsible for BMDC inflammasome activation. In contrast, human monocyte-derived DCs (mDCs) released IL-1β even in the absence of toxins suggesting host-specific mediation. Infected DC-T cell crosstalk revealed the ability of R20291 and 630 WT strains to elicit a differential DC IL-12 family cytokine milieu which culminated in significantly greater Th1 immunity in response to R20291. Interestingly, both strains induced a similar Th17 response. Elicitation of mucosal IFN-γ/IL-17A and Th1/Th17 immunity to C. difficile indicates a central role for this dual cytokine axis in establishing antimicrobial immunity to CDI.

Phenotypic and genotypic characterisation of inflammatory bowel disease presenting before the age of 2 years

Objectives: Inflammatory bowel disease [IBD] presenting in early childhood is extremely rare. More recently, progress has been made to identify children with monogenic forms of IBD predominantly presenting very early in life. In this study, we describe the heterogeneous phenotypes and genotypes of patients with IBD presenting before the age of 2 years and establish phenotypic features associated with underlying monogenicity. Methods: Phenotype data of 62 children with disease onset before the age of 2 years presenting over the past 20 years were reviewed. Children without previously established genetic diagnosis were prospectively recruited for next-generation sequencing. Results: In all, 62 patients [55% male] were identified. The median disease onset was 3 months of age (interquartile range [IQR]: 1 to 11). Conventional IBD classification only applied to 15 patients with Crohn’s disease [CD]-like [24%] and three with ulcerative colitis [UC]-like [5%] phenotype; 44 patients [71%] were diagnosed with otherwise unclassifiable IBD. Patients frequently required parenteral nutrition [40%], extensive immunosuppression [31%], haematopoietic stem-cell transplantation [29%], and abdominal surgery [19%]. In 31% of patients, underlying monogenic diseases were established [EPCAM, IL10, IL10RA, IL10RB, FOXP3, LRBA, SKIV2L, TTC37, TTC7A]. Phenotypic features significantly more prevalent in monogenic IBD were: consanguinity, disease onset before the 6th month of life, stunting, extensive intestinal disease and histological evidence of epithelial abnormalities. Conclusions: IBD in children with disease onset before the age of 2 years is frequently unclassifiable into Crohn’s disease and ulcerative colitis, particularly treatment resistant, and can be indistinguishable from monogenic diseases with IBD-like phenotype.

Gastrointestinal endoscopy and mucosal biopsy in the first year of life: indications and outcome.

Objectives: Lower threshold and widening indications for paediatric gastrointestinal endoscopy have resulted in a significant increase in the numbers of endoscopic procedures performed in infants. Despite this, knowledge of gastrointestinal mucosal findings in this age group is limited and data on the clinical usefulness of endoscopy are lacking. Methods: All of the children younger than 1 year referred to a single tertiary paediatric gastroenterology unit during the period June 1987 to August 2007 who underwent gastrointestinal endoscopy were identified and the clinical indications and histological outcomes were reviewed. Results: A total of 933 gastroesophageal duodenoscopies and 439 colonoscopies were performed in 1024 cases in a total of 823 infants. In order of frequency, clinical indications were diarrhoea (51%), failure to thrive (41.2%), symptoms of reflux (27.1%), and rectal bleeding (8.5%). Mucosal biopsies were insufficient for assessment in only 2.4% of cases. Mucosal histology was normal in 33.8%, whereas histological abnormalities were identified in 63.8%. Specific histological diagnoses included microvillous inclusion disease, autoimmune enteropathy, graft-versus-host disease post–bone marrow transplantation, tufting enteropathy, and disaccharidase deficiency. There was only 1 colonic perforation complicating endoscopy in a total of 889 cases for which relevant information was available (0.1%). Conclusions: In two-thirds of cases, histological abnormalities were detected that influenced management following endoscopic examination and mucosal biopsy in infants. Endoscopy with biopsies is a greatly informative test with low failure and complication rates in the first year of life.

Granulomatous pneumonitis, sclerosing cholangitis, and pancreatitis in a child with Crohn disease: response to infliximab.

Fulminating acute ulcerative colitis (UC) is a potentially life threatening medical emergency. Up to 30% of individuals respond poorly to corticosteroids alone and second line medical or surgical therapies are indicated. We describe the successful use of chimeric anti-CD25 therapy in 4 such children poorly responsive to combined therapy with intravenous steroids and calcineurin inhibitors with a pretreatment predictive risk of colectomy of 85-100%. Clinical disease activity scores normalized within 72 hours of anti-CD25 administration and colonic histology provided evidence of mucosal healing within 10-14 days. None required emergency colectomy. Anti-CD25 is efficacious in fulminating UC and randomized placebo controlled trials appear indicated.

The use of sirolimus (rapamycin) in the management of refractory inflammatory bowel disease in children

BACKGROUND Management of refractory inflammatory bowel disease (IBD) in children is challenging and once response to conventional medical therapy deviates from the expected, options are often limited. Sirolimus is commonly used in post-transplantation management and is used sparsely as rescue therapy in refractory Crohns disease. In the present study, we report the efficacy of sirolimus as an adjuvant immunosuppressive therapy in a retrospective case review of a selected group of IBD children who were refractory to the conventional treatments. METHODS Medical records of children with refractory IBD unresponsive to conventional therapy and started on sirolimus between 2006 and 2012 were retrospectively reviewed. Clinical response, through Pediatric Ulcerative Colitis Activity Index (PUCAI) and Pediatric Crohns Disease Activity Index (PCDAI), as well as intestinal inflammation, through specific histological scores, was evaluated. RESULTS The records of 14 patients were analyzed. Eleven of them had ulcerative colitis (UC) and 3 Crohns disease (CD); mean age at diagnosis was 9.1 years (standard deviation 3.8). Of UC patients, 5 (45%) achieved clinical remission and 2 (18%) showed clinical response. All CD patients went into clinical remission. Mucosal healing was achieved by 5 children (45%) with UC and 2 (67%) with CD patients. One child with ulcerative colitis was weaned off adalimumab, while 2 children with CD were weaned off prednisolone and methotrexate successfully. CONCLUSION Our data provide evidence that sirolimus seems to be effective as rescue therapy in a subgroup of children with severe IBD refractory to conventional therapies by inducing both clinical remission and mucosal healing.