Faubion, William A.

ABSTRACTObjectives:Despite a paucity of published supporting data, 5‐aminosalicylate (5‐ASA) use in pediatric ulcerative colitis (UC) is common. The present study describes the use and outcome of a large multicenter inception cohort of children with UC treated with 5‐ASA.Methods:Data were obtained from the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry, a prospective North American observational study of children newly diagnosed as having inflammatory bowel disease ages 16 years or younger. Patient data are recorded at diagnosis, 30 days, and then quarterly. Patients are managed by physician dictate, not protocol. Disease activity is classified by physician global assessment. The primary outcome examined was corticosteroid (CS) free, inactive UC at 1 year following initiation of 5‐ASA within 30 days of diagnosis (with or without concomitant CS use) without the need for rescue therapy (immunomodulators, biologics, or colectomy).Results:Study subjects included 213 patients newly diagnosed as having UC who received oral 5‐ASA compounds (115 of whom also received CS) during the first 30 days after diagnosis, and no other oral therapies for the treatment of UC. Of these 213 patients, 86 (40%) were CS free and physician global assessment inactive at 1 year without rescue. Outcome was not associated with disease severity at diagnosis, demographic or laboratory factors examined, or initial dose of 5‐ASA used.Conclusions:Forty percent of children taking 5‐ASA as primary maintenance therapy at diagnosis are in CS‐free remission after 1 year of treatment. Further pediatric studies will be needed to address whether increased adherence and/or higher dosing schedules will improve outcomes.

ABSTRACTObjectives:Small bowel intraepithelial lymphocytosis (IELs) with normal villous architecture is a relatively common finding, often of uncertain significance. The aims of our study were to determine the prevalence of this finding, its clinical associations, its specificity for celiac disease (CD), and whether histologic clues exist that increase the specificity for CD in this setting, all in the pediatric population.Methods:The Mayo Clinic electronic pathology database was searched between January 1, 2000 and December 31, 2009 for patients younger than 18 years who had the terms “normal villi” and “increased intraepithelial lymphocytes” in their small bowel biopsy reports. All of the slides were reviewed to confirm the histologic findings. Demographic, serologic, pathologic, and clinical informations were obtained.Results:Among 1290 duodenal biopsies obtained from children during the years 2000 and 2009, 56 (4.3%) were noted to have “normal villous architecture with increased intraepithelial lymphocytes.” In the 54 patients not known to have CD before biopsy, 48 (89%) had serologic testing for CD. Of these 48 patients, 9 were labeled with CD, although only 5 of 9 met the definite criteria for the diagnosis, based on a combination of serologic markers, human leukocyte antigen haplotyping, and response to gluten‐free diet. No clinical features pointed to a diagnosis of CD. There was no correlation between CD and number of IELs, but patients with newly diagnosed CD were more likely to have a tip‐heavy lymphocyte distribution. Other diagnoses made during the study period and in follow‐up were inflammatory bowel disease (5), Helicobacter pylori infection (3), medication‐related injury (10), and systemic autoimmune disorders (2).Conclusions:Increased IELs with normal villous architecture in small bowel biopsies are clinically important in children, and are associated with a new definite diagnosis of CD in 9% of pediatric patients. Even at this low sensitivity, clinical work‐up for CD is mandated in all of the patients with this finding.

ABSTRACTUlcerative colitis (UC) and Crohn disease (CD), collectively referred to as inflammatory bowel disease (IBD), are chronic inflammatory disorders that can affect the gastrointestinal tract of children and adults. Like other autoimmune processes, the cause(s) of these disorders remain unknown but likely involves some interplay between genetic vulnerability and environmental factors. Children, in particular with UC or CD, can present to their primary care providers with similar symptoms, including abdominal pain, diarrhea, weight loss, and bloody stool. Although UC and CD are more predominant in adults, epidemiologic studies have demonstrated that a significant percentage of these patients were diagnosed during childhood. The chronic nature of the inflammatory process observed in these children and the waxing and waning nature of their clinical symptoms can be especially disruptive to their physical, social, and academic development. As such, physicians caring for children must consider these diseases when evaluating patients with compatible symptoms. Recent research efforts have made available a variety of more specific and effective pharmacologic agents and improved endoscopic and radiologic assessment tools to assist clinicians in the diagnosis and interval assessment of their patients with IBD; however, as the level of complexity of these interventions has increased, so too has the need for practitioners to become familiar with a wider array of treatments and the risks and benefits of particular diagnostic testing. Nonetheless, in most cases, and especially when frequent visits to subspecialty referral centers are not geographically feasible, primary care providers can be active participants in the management of their pediatric patients with IBD. The goal of this article is to educate and assist pediatricians and adult gastroenterology physicians caring for children with IBD, and in doing so, help to develop more collaborative care plans between primary care and subspecialty providers.

Abstract The expression of pathogen recognition receptors in human FOXP3+ T regulatory cells is established, yet the function of these receptors is currently obscure. In the process of studying the function of both peripheral and lamina propria FOXP3+ lymphocytes in patients with the human inflammatory bowel disease Crohn’s disease, we observed a clear deficiency in the quantity of FOXP3+ lymphocytes in patients with disease-associated polymorphisms in the pathogen recognition receptor gene NOD2. Subsequently, we determined that the NOD2 ligand, muramyl dipeptide (MDP), activates NF-κB in primary human FOXP3+ T cells. This activation is functionally relevant, as MDP-stimulated human FOXP3+ T cells are protected from death receptor Fas-mediated apoptosis. Importantly, apoptosis protection was not evident in MDP-stimulated FOXP3+ T cells isolated from a patient with the disease-associated polymorphism. Thus, we propose that one function of pathogen recognition receptors in human T regulatory cells is the protection against death receptor-mediated apoptosis in a Fas ligand-rich environment, such as that of the inflamed intestinal subepithelial space.

The C-type lectin-like receptor CD161, which has recently been described to promote T cell expansion, is expressed on a discrete subset of human CD4 T cells. The function of such cells, however, has remained elusive. We now demonstrate that CD161+ CD4 T cells comprise a circulating and gut-resident T helper 17 (Th17) cell population. During Crohn's disease (CD), these CD161+ cells display an activated Th17 phenotype, as indicated by increased expression of interleukin (IL)-17, IL-22, and IL-23 receptor. CD161+ CD4 T cells from CD patients readily produce IL-17 and interferon γ upon stimulation with IL-23, whereas, in healthy subjects, priming by additional inflammatory stimuli such as IL-1β was required to enable IL-23–induced cytokine release. Circulating CD161+ Th17 cells are imprinted for gut homing, as indicated by high levels of CC chemokine receptor 6 and integrin β7 expression. Supporting their colitogenic phenotype, CD161+ Th17 cells were found in increased numbers in the inflammatory infiltrate of CD lesions and induced expression of inflammatory mediators by intestinal cells. Our data identify CD161+ CD4 T cells as a resting Th17 pool that can be activated by IL-23 and mediate destructive tissue inflammation.