IL-10-producing regulatory cells impact on celiac disease evolution.

Celiac Disease (CD) is a T-cell mediated disorder caused by immune response to gluten, although the mechanisms underlying CD progression are still elusive. We analyzed immune cell composition, plasma cytokines, and gliadin-specific T-cell responses in patients with positive serology and normal intestinal mucosa (potential-CD) or villous atrophy (acute-CD), and after gluten-free diet (GFD). We found: an inflammatory signature and the presence of circulating gliadin-specific IFN-γ+ T cells in CD patients regardless of mucosal damage; an increased frequency of IL-10-secreting dendritic cells (DC-10) in the gut and of circulating gliadin-specific IL-10-secreting T cells in potential-CD; IL-10 inhibition increased IFN-γ secretion by gliadin-specific intestinal T cells from acute- and potential-CD. On GFD, inflammatory cytokines normalized, while IL-10-producing T cells accumulated in the gut. We show that IL-10-producing cells are fundamental in controlling pathological T-cell responses to gluten: DC-10 protect the intestinal mucosa from damage and represent a marker of potential-CD.

Tolerogenic IL-10-engineered dendritic cell-based therapy to restore antigen-specific tolerance in T cell mediated diseases.

Tolerogenic dendritic cells play a critical role in promoting antigen-specific tolerance via dampening of T cell responses, induction of pathogenic T cell exhaustion and antigen-specific regulatory T cells. Here we efficiently generate tolerogenic dendritic cells by genetic engineering of monocytes with lentiviral vectors co-encoding for immunodominant antigen-derived peptides and IL-10. These transduced dendritic cells (designated DCIL-10/Ag) secrete IL-10 and efficiently downregulate antigen-specific CD4+ and CD8+ T cell responses from healthy subjects and celiac disease patients in vitro. In addition, DCIL-10/Ag induce antigen-specific CD49b+LAG-3+ T cells, which display the T regulatory type 1 (Tr1) cell gene signature. Administration of DCIL-10/Ag resulted in the induction of antigen-specific Tr1 cells in chimeric transplanted mice and the prevention of type 1 diabetes in pre-clinical disease models. Subsequent transfer of these antigen-specific T cells completely prevented type 1 diabetes development. Collectively these data indicate that DCIL-10/Ag represent a platform to induce stable antigen-specific tolerance to control T-cell mediated diseases.

Children With Inflammatory Bowel Disease in the COVID-19 Main Endemic Focus: The Lombardy Experience.

Objectives: In the era of Coronavirus 2019 (COVID-19), concern has been raised for immunosuppressed patients, including children with inflammatory bowel diseases (IBD). We aimed to collect data from IBD tertiary centers of Lombardy during pandemic. Methods: A cross-sectional survey enrolling IBD children has been completed by seven major IBD centers in Lombardy during lockdown. The clinical form included questions on any symptom consistent with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the IBD adherence treatment. Furthermore, we have reviewed all IBD medical records including new IBD diagnoses and flares in known IBD patients after the lockdown. Results: Questionnaires of 290 IBD children were returned during lockdown. Out of them, 24 children (8%) complained of mild symptoms suspicious of SARS-CoV-2 infection without needing hospitalization or changing IBD treatment. During the lockdown, one patient presented with IBD flare and one had infectious colitis, with no new IBD cases. Conversely, after lockdown, 12/290 (4%) children relapsed and 15 children were newly diagnosed with IBD. Last year, in the same timeframe, 20/300 (7%) children presented with IBD flare, while 17 children had IBD onset with no statistical difference. Conclusions: Our data on children with IBD in a high COVID-19 prevalence region are reassuring. Only a minority of IBD children had mild symptoms, and no hospitalization or treatment modification was needed. Standard IBD treatments including biologics were safely continued. New IBD diagnoses and flares in known IBD children occurred after the lockdown phase, although no significant difference was found compared with the previous year.