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We report the first case series of ICI-associated colitis successfully treated with fecal microbiota transplantation (FMT), with reconstitution of the gut microbiome and a relative increase in the proportion of regulatory T cells (Tregs) within the colonic mucosa. These preliminary data provide evidence that modulation of the gut microbiome may abrogate ICI-associated colitis.

10.1093/ibd/izy104_video1izy104.video15808053084001.

BackgroundImmune checkpoint inhibitors (ICPI) are efficacious treatments for advanced malignancies but can result in immune mediated diarrhea and colitis (IDC). Currently, the guidelines for the treatment of IDC depend only on clinical symptoms. Endoscopic and histologic features of such adverse events are not well studied in a manner that can help to gauge treatment plans. We aimed to characterize endoscopic and histologic features of IDC and to assess their association with clinical outcomes.MethodsOur study included patients who had undergone endoscopy for IDC (1/2010 to 3/2018). Patients with GI infection at time of onset were excluded. High-risk endoscopic features were ulcers deeper than 2 mm, larger than 1 cm, and extensive colonic involvement. Univariate and multivariate logistic regression were performed to assess the association of endoscopic and histological features with clinical outcomes.ResultsA total of 182 patients was included; most were white (92%), males (65%) with a mean age of 60 years. Median time from ICPI initiation to IDC was 7 weeks. Fifty-three percent had grade 3–4 diarrhea, and 32% grade 3–4 colitis. Forty-nine patients had mucosal ulcerations, 66 non-ulcerative inflammation and 67 normal endoscopy. Calprotectin was higher in patients with ulceration (P = 0.04). The sensitivity of lactoferrin to detect histologic and endoscopic inflammation was 90% and 70% respectively. Patients who underwent endoscopy earlier than 7 days after IDC onset had shorter duration of IDC symptoms and duration of steroid treatment than those who underwent endoscopy after 7 days of IDC onset (P = 0.026 and P = 0.053, respectively). Patients who underwent endoscopy > 30 days of symptom onset required longer duration of steroids (P = 0.02), had more recurrent symptoms (P < 0.01) and received later infliximab/vedolizumab add-on therapy than did those who underwent endoscopy ≤30 days (P = 0.03). High-risk features were associated with more frequent (P = 0.03) and longer duration (P = 0.02) hospitalization and infliximab/vedolizumab requirement (P < 0.01). Patients with active histological inflammation had more recurrence (P < 0.01) and repeat endoscopy (P < 0.01). Repeat endoscopy was required in 47 patients. A multivariate logistic regression revealed that longer ICPI treatment was associated with more frequent hospitalizations (OR 1.00; 95%CI 1.00–1.01; P < 0.01) and high-risk endoscopic features were associated with the requirement of infliximab/vedolizumab (OR 3.89; 95%CI 1.68–9.01; P < 0.01).ConclusionHigh risk endoscopic features and active histologic inflammation represent important markers of disease severity with clinical implications and should be used in a timely manner to devise IDC-focused treatment algorithms.Electronic supplementary materialThe online version of this article (10.1186/s40425-018-0411-1) contains supplementary material, which is available to authorized users.

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BackgroundImmune checkpoint inhibitors (ICPIs) are gaining increasing popularity as an efficacious treatment for advanced malignancies. ICPI treatment can be complicated by diarrhea and colitis. Systemic steroids are the first line treatment. Infliximab is reserved for severe refractory cases. We aimed to assess the impact of ICPI-induced diarrhea and colitis and their immunosuppressive treatment on patients’ outcomes.MethodsThis retrospective analysis was conducted in 327 cancer patients who received ICPIs between 2011 and 2017. Patients with ICPI-induced toxicities in other organs were excluded. We collected data about patient demographics, clinical variables, and overall survival. We used descriptive analysis to compare different groups based on the occurrence and the treatment of diarrhea and colitis. Kaplan-Meier and log-rank test were used to estimate and compare overall survival durations between groups.ResultsDiarrhea was recorded in 117 (36%) patients; 79 (24%) of them required immunosuppressive treatment of either systemic corticosteroid without infliximab (n = 44) or with infliximab (n = 35). Caucasian ethnicity, melanoma, stage 3 cancer, and ipilimumab were predictors of colitis that requires immunosuppression. Patients who required immunosuppressants had better overall survival than those who did not require treatment for colitis or diarrhea (P < 0.001). Immunosuppression for diarrhea or colitis did not affect the overall survival significantly (P = 0.232), nor did the choice of treatment (corticosteroids with vs. without infliximab; P = 0.768). Diarrhea was an independent predictor of a favorable overall survival (P < 0.001), irrespective of treatment need (P = 0.003). We confirmed the same results in a subgroup analysis for patients with stage IV malignancies only. Patients who received long duration of steroid treatment (> 30 days) had numerically higher infection rate than those who received steroid for shorter duration (40.4 vs. 25.8%, P = 0.160). Likewise, long duration of steroid without infliximab was associated with increased risk of infection compared to short duration of steroid with infliximab (42.9% vs. 14.3%, P = 0.089).ConclusionsPatients with ICPI-induced diarrhea or colitis have improved survival outcomes. Diarrhea is an independent predictor of an improved survival regardless of treatment requirement. Immunosuppressive treatment for diarrhea did not significantly affect overall survival, however, infection rates were numerically higher among patients who received steroids for a long duration. Therefore, early non-steroid immunosuppressive therapy may ensure a more favorable overall outcome.

Background & Aims A prominent role for inhibitory molecules PD-L1 and PD-L2 in peripheral tolerance has been proposed. However, the phenotype and function of PD-L-expressing cells in human gut remains unclear. Recent studies suggest that intestinal myofibroblasts (CMFs) and fibroblasts are important in the switch from acute inflammation to adaptive immunity. In the normal human colon CMFs represent a distinct population of MHC class II+ cells involved in the regulation of mucosal CD4+ T cell responses. Methods PD-L1 and PD-L2 expression on human CMFs was determined using Western Blot, FACS analysis and confocal microscopy. Lymphoproliferation assays and cytokine ELISAs were used to evaluate the role of B7 co-stimulators expressed by CMFs with regard to the regulation of preactivated T helper cell responses. Results We demonstrate here the expression of PD-L1/2 molecules by normal human colonic myofibroblasts and fibroblasts in situ and in culture. Both molecules support suppressive functions of CMFs in the regulation of activated CD4+ T helper cell proliferative responses, since blocking this interaction reverses the suppressive effect of CMFs on T cell proliferation and leads to increased production of the major T cell growth factor, IL-2. PD-L1/2-mediated CMF suppressive functions are mainly due to the inhibition of IL-2 production, since supplementation of the co-culture media with exogenous IL-2 led to partial recovery of activated T cell proliferation. Conclusions Our data suggest that stromal myofibroblasts and fibroblasts may limit T helper cell proliferative activity in the gut and, thus, might play a prominent role in mucosal intestinal tolerance.

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