Pediatric refractory Inflammatory Bowel Disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract, not responsive to current treatments. Since hematopoietic stem and progenitor cells (HSPCs) in the bone marrow display immunomodulatory functions and IL-10-producing regulatory cells regulate gut homeostasis, by combining state-of-the-art strategies for the ex-vivo manipulation and expansion of HSPCs and gene delivery systems to drive HLA-class II-restricted antigen presentation and expression of tolerogenic molecules, the investigators propose to dissect the antigen- (Ag-) presenting capacity of HSPCs and to exploit their tolerogenic potential to induce IL-10-mediated tolerance in the intestinal mucosa of IBD patients. The investigators hypothesize that HSPCs can be engineered using commensal-derived Ags w/wo IL-10 to drive the differentiation of Tr1 cells with the desired Ag-specificity to control intestinal inflammation in IBD. The results of this study will pave the way for defining innovative cell-based approaches for treating refractory pediatric IBD.
Inflammatory Bowel Disease (IBD) is a chronic inflammatory condition affecting the gastrointestinal tract, with Crohn's Disease (CD) and Ulcerative Colitis (UC) being the main types. The causes of IBD are complex and include immune dysregulation with activation of immune cells, release of inflammatory cytokines, and intestinal tissue damage. Despite significant advances in the treatment of pediatric IBD, a large unmet need for a definitive cure remains, and cell immunotherapy is under investigation. The investigators are specifically interested in refractory IBD, a chronic active condition requiring continuous treatment for symptom relief, with detrimental side effects. Despite the several treatment options currently available, 30% of pediatric IBD patients are refractory, and none of the existing treatments results in complete remission. Interleukin 10 (IL-10) is an immunoregulatory cytokine associated with IBD pathogenesis and regulating gut homeostasis. Type 1 regulatory T (Tr1) cells produce IL-10 and their function is crucial for suppression of inflammation in IBD. The investigators recently published that antigen (Ag)-specific immune responses in Celiac Disease can be controlled via IL-10-producing Ag-presenting cells engineered to express a gliadin epitope, demonstrating that Ag-presenting cells can be manipulated to promote Tr1 cell differentiation. Significant advances in the field of hematopoietic stem and progenitor cells (HSPCs) engineering and biology have been achieved. The development of protocols for ex-vivo manipulation and expansion of circulating (c)HSPCs and of mobilization-based chemotherapy-free approaches broadens the applicability of HSPC-based therapies to diseases for which HSPC transplantation is not the standard of care. A recent report showed that Tr1 cells can be promoted by immunogenic HSPC, which present Ags via HLA class II to CD4+ T cells in the bone marrow. This discovery opens new avenues for the development of approaches exploiting the Ag-presenting capacity and the tolerogenic potential of HSPCs to counteract inflammation in target tissues. Based on these premises, with the final goal of developing a procedure for the induction of IL-10-mediated tolerance to control intestinal inflammation in refractory IBD pediatric patients, the investigators will: * Investigate the type and frequency of inflammatory and regulatory immune cells, including IL-10-related regulatory cells, infiltrating the gut mucosa of IBD and non-IBD control patients. Results will indicate whether enforcement of the regulatory arm would benefit IBD patients. To this aim, it is necessary to collect and analyze intestinal tissue fragments from IBD and non-IBD control patients. * Investigate the type and frequency of immune cells, including IL-10-related regulatory cells, circulating in the peripheral blood of IBD patients and non-IBD control patients. Results will indicate whether enforcement of the regulatory arm would benefit IBD patients. To this aim it is necessary to collect PB from IBD and non-IBD control patients. * Characterize the presence, phenotype, and expansion potential of CD34+ HSPCs circulating in the peripheral blood of IBD patients. To this end, the investigators will collect peripheral blood from IBD patients, and i) assess the frequency, composition, and Ag-presenting potential of and ii) apply ex-vivo expansion and engineering protocols to CD34+ HSPC circulating in the peripheral blood of IBD patients. These results will be pivotal for assessing the feasibility of HSPC-based approaches to restore homeostasis in the intestinal tissue in refractory pediatric IBD. * Evaluate the response to commensal-derived Ags (e.g., Bacteroides-derived peptides) of CD4+ T lymphocytes circulating by collecting the peripheral blood of IBD patients, non-IBD control patients, and healthy subjects as control. These results will indicate which Ag could be used for HSPC engineering and for inducing IL-10-producing regulatory T cells. * Assess the ability of human HSPCs to promote Ag-specific Tr1 cells in vitro. To this end, selected IBD patients known to be responders commensal -derived Ags (as above) and peripheral blood will be collected at 1 year (6-18 months) follow-up. The investigators will engineer circulating HSPCs ex-vivo expanded from the peripheral blood of selected IBD patients and test for their ability to promote Ag-specific Tr1 cell upon in vitro culture with autologous CD4+ T cells.
Study Type
OBSERVATIONAL
Enrollment
80
An additional volume of peripheral blood (3-10 ml) will be obtained in concomitance with clinically indicated procedures
A small fragment (1-5 mm) of intestinal tissue - residual or leftover material -will be obtained from patients undergoing diagnostic or follow-up endoscopy
Peripheral blood samples from healthy subjects, leftover from TIGET09 protocol analysis will be collected
Pediatric Immunohematology Unit, IRCCS Ospedale San Raffaele
Milan, Italy
UOC Pediatria, Azienda Ospedaliero-Universitaria Sant'Andrea
Rome, Italy
To characterize pediatric IBD patients' peripheral blood and intestinal mucosa immune cell composition
Frequency (%) of predefined regulatory and inflammatory immune-cell subsets in peripheral blood and gut mucosa, including regulatory T cells (FOXP3+ Tregs and IL-10 producing Tr1 cells), T naïve/memory and effector cells, regulatory myeloid cells (DC-10), and inflammatory myeloid cells (cDC1 and cDC2), measured by flow cytometry. The primary objective will be considered met if patients with IBD show a lower frequency of IL-10-producing cells than controls, with the estimated between-group difference supporting a defect in IL-10-producing cell responses.
Time frame: Baseline timepoint
To explore the ability of HSPCs to induce in vitro the differentiation of Ag-specific Tr1 cells.
Induction of Tr1-like cells following T-cell/HSPC co-culture, assessed by: frequency (%) of cells expressing the Tr1-associated phenotype and expression of Tr1-associated genes. Success criterion (exploratory): Generation of a T-cell population displaying Tr1-associated features.
Time frame: Baseline and 1 year follow up
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