Mucosal IL-10 and IL-10 receptor expression patterns in paediatric patients with ulcerative colitis.

Interleukin-10 (IL-10) is a key anti-inflammatory cytokine. We aimed to assess IL-10 and IL-10 receptor (IL-10R) expression in the gut, and determine whether these patterns are altered in patients with ulcerative colitis (UC). Formalin-fixed paraffin-embedded rectal and transverse colon sections were collected from three groups of patients: (a) control subjects with normal colonoscopy and without history of inflammatory bowel disease; (b) UC patients with extensive colitis or pancolitis (E3/E4 phenotype); and (c) UC patients with limited distal disease (E1/E2 phenotype; n = 8-10 subjects per group). Immunohistochemistry (IHC) was performed to assess expression patterns of IL-10, IL-10R1 and IL-10R2, and was correlated with clinical, endoscopic and histologic severity indices among patients. A trend towards increased IL-10 expression was noted in rectal biopsies of patients with active UC, compared with controls. Moreover, IL-10 levels were significantly increased in transverse colon biopsies of patients with extensive/pancolitis, compared with control subjects and patients with limited distal disease. Rectal IL-10R1 and IL-10R2 levels were comparable between control subject and patients with active UC. However, transverse colon IL-10R1 levels were significantly higher in patients with E3/E4 colitis, compared with controls. Finally, we found no correlation between clinical, endoscopic and histologic severity of inflammation among UC patients and IL-10, IL-10R1 or IL-10R2 expression in rectal sections. Mucosal expression patterns of IL-10 and IL-10R, evaluated by IHC, were overall similar between control subjects and patients with active UC. Given IL-10's anti-inflammatory properties, additional studies are required to determine whether signalling through the IL-10R is altered among these patients.

Antibodies Against Glycoprotein 2 Are Specific Biomarkers for Pediatric Crohn's Disease.

BACKGROUND: Serological markers can assist in accurate differentiation between Crohn's disease (CD) and ulcerative colitis (UC). One such marker is anti-glycoprotein 2 (anti-GP2) which was shown to be a specific marker for CD in adult patients. The aim of our study was to assess the utility of anti-GP2 and GP2 as biomarkers for pediatric CD, and determine whether they correlate with disease activity. METHODS: Serum samples were tested by ELISA for anti-GP2 isoform 4 IgG and IgA, and also for GP2. Results were correlated with demographic and clinical data. RESULTS: The cohort consisted of 53 pediatric patients with CD, 42 with UC, and 53 controls. Levels of anti-GP2 were significantly increased in pediatric patients with CD in comparison with patients with UC, and control subjects, with high positive predictive value for both IgG and IgA (97.9% and 82.6%, respectively). While specificity of anti-GP2 IgG and IgA was very high (98.7% and 90.0%, respectively), sensitivity was low (42.0% and 35.5% for IgG and IgA, respectively). In CD, anti-GP2 correlated with disease activity, and decreased in treatment-naïve patients following successful induction therapy. A higher IgA anti-GP2 was also demonstrated in patients with ileo-colonic involvement, and was associated with a younger age. Finally, positive GP2 level was identified in only 1/211 serum samples. CONCLUSIONS: A positive anti-GP2 level is highly associated with CD, while a negative result does not exclude CD. Additional studies are required to determine whether these markers can be used in pediatric patients with CD for risk stratification.

Monogenic Inflammatory Bowel Disease: It's Never Too Late to Make a Diagnosis.

Background: More than 50 different monogenic disorders have been identified as directly causing inflammatory bowel diseases, typically manifesting in the first years of life. We present the clinical course and immunological work-up of an adult patient who presented in adolescent years with an atypical gastrointestinal phenotype and was diagnosed more than two decades later with a monogenic disorder with important therapeutic implications. Methods: Whole exome sequencing was performed in a 37-years-old patient with a history of diarrhea since adolescence. Sanger sequencing was used to validate the suspected variant. Mass cytometry (CyTOF) and flow cytometry were conducted on peripheral blood mononuclear cells for deep immunophenotyping. Next-generation sequencing of the TCRB and IgH was performed for global immune repertoire analysis of circulating lymphocytes. Results: We identified a novel deleterious c.1455C>A (p.Y485X) mutation in LRBA. CyTOF studies demonstrated significant changes in immune landscape in the LRBA-deficient patient, including an increase in myeloid derived suppressor cells and double-negative T cells, decreased B cells, low ratio of naïve:memory T cells, and reduced capacity of T cells to secrete various cytokines following stimulation, including tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). In addition, this patient exhibited low frequency of regulatory T cells, with a reduction in their CTLA4 expression and interleukin (IL)-10 secretion. Finally, we show marked oligoclonal expansion of specific B- and T-cell clones in the peripheral blood of the LRBA-deficient patient. Conclusions: LRBA deficiency is characterized by marked immunological changes in innate and adaptive immune cells. This case highlights the importance of advanced genetic studies in patients with a unique phenotype, regardless of their age at presentation.

Circulating α4ß7+ Memory T Cells in Pediatric IBD Patients Express a Polyclonal T Cell Receptor Repertoire.

BACKGROUND: The integrin α4ß7 is highly expressed on activated T cells and is thought to direct homing of lymphocytes to the intestine. Since ulcerative colitis (UC) and Crohn's disease (CD) are characterized by mucosal oligoclonal T cells' expansion, we aimed to assess whether similar repertoire features are identified in circulating gut-specific memory T cells. METHODS: Memory CD3+ T cells were isolated from blood samples of control subjects and patients with active UC or CD and then FACS-sorted into α4ß7+ and α4ß7- populations. DNA was extracted from each subset and subjected to next-generation sequencing of the TCRß. Different repertoire characteristics were compared between α4ß7+ and α4ß7- subsets for each subject, and between groups. RESULTS: The percentages of memory T cells and α4ß7+ cells were comparable between groups. α4ß7+ memory T cells displayed a polyclonal distribution, in control subjects and in UC or CD patients, with similar indices of diversity. Strikingly, the clonal overlap between α4ß7+ and α4ß7- T cells for each subject in all three groups was high, ranging between 20%-50%. We were unable to identify shared T cell clones that were specific to one of the groups. CONCLUSION: α4ß7+ memory T cells exhibited a polyclonal repertoire in both control subjects and patients with active inflammatory bowel disease, with high rates of overlap with α4ß7- memory T cells. Our study, along with additional recent reports, may suggest that the suppression of intestinal inflammation by vedolizumab is independent of the drug's effect on T cell migration to the gut.