Digestive Disease Week 2023

BACKGROUND: Prevention of postoperative recurrence (POR) in Crohn’s disease (CD) after ileo-colonic (IC) resection is still a highly debated topic. Prophylactic immunosuppression after surgery is currently recommended in presence of at least one clinical risk factor (RF). Due to drug-related adverse events and the relative high cost of biologics, we aimed to determine whether prevention of POR can be postponed and guided by endoscopy in CD patients with only one RF.
METHODS: A multicentre retrospective study was conducted in 12 Italian centres. CD patients with only one RF for POR, including previous intestinal resection, extensive small intestine resection (>50 cm), fistulising phenotype, history of perianal disease, or active smoking were considered. Patients who performed a colonoscopy between 6 to 12 months after curative IC resection were included. Two groups were formed based on whether immunosuppressive therapy was started immediately after surgery (prophylaxis group) or guided by endoscopy (observation group). Primary endpoints were the rates of any endoscopic recurrence (Rutgeerts ≥i2a) and severe endoscopic recurrence (i4) within 12 months after surgery. Secondary outcomes were clinical recurrence (HBI≥5) rates at 6, 12 and 24 months after surgery.
RESULTS: A total of 195 patients were enrolled. Out of all, 61 (31.3%) received immunoprophylaxis at a median time of 32 days [IQR 26-55] after surgery (n=14 infliximab, n=37 adalimumab, n=7 azathioprine, n=3 ustekinumab). Baseline patient characteristics are detailed in Table 1. Particularly, risk factors for POR were homogeneously distributed between the 2 groups. Colonoscopy was performed after a median time of 8 months [IQR 6-11]. No differences between immunoprophylaxis and endoscopy-driven approach was found regarding any endoscopic recurrence (36.1% in prophylaxis group vs 45.5% in observation group, p=0.10) and severe endoscopic recurrence (9.8% in prophylaxis group vs 15.7% in observation group, p=0.15). In 32 patients with a second colonoscopy at a median time of 30.5 months [IQR 22-43.75] after surgery, any recurrence and severe recurrence rates were also similar (p=0.55 and p=0.43, respectively).
Early clinical recurrence at 6 months was reported in 23.4% of patients on immunoprophylaxis vs 31.5% who were not (p=0.43). Clinical recurrence rates between prophylaxis and observation group were also similar at 12 months (17.9% vs 34.8%, respectively, p=0.09) and at 24 months (17.9% vs 24.1%, respectively, p=0.63).
CONCLUSION: In CD patients with only one RF for POR, immediate immunoprophylaxis after curative IC resection does not decrease the rate of early clinical and endoscopic recurrence. Prospective and larger studies are needed to confirm our results.

Background: Contamination-free oats are considered safe for most patients with celiac disease (CeD). However, we and others have isolated pro-inflammatory oat protein (avenin)-specific CD4+ T cells from the blood and duodenum of some people with CeD, a finding that carries troubling implications for safe oats ingestion in CeD. Does the presence of avenin-specific T cells identify CeD patients susceptible to harm from oats?
Aim: To determine the frequency of symptoms and immune activation in patients with CeD after single-bolus ingestion of purified avenin and then assess symptomatic, immune and clinical (safety) effects after extended avenin ingestion.
Methods: For the first time, food-grade avenin was purified from contamination-free oats to enable feeding studies at high doses not achievable using oats. We employed a series of single-bolus avenin challenges in HLA-DQ2.5+ CeD adults with assessment of symptoms and serum interleukin (IL)-2 at 4 hrs, a highly sensitive marker of gluten-specific T cell activation. Avenin was given in increasing amounts (0.05, 0.1, 0.5, 1, 4, and 6 g) with 4-wk washout periods. Subsequently, in patients with IL-2 responses, avenin was consumed daily for 6 wks at the highest tolerated dose that triggered IL-2. T-cells were assessed using avenin-specific tetramers, serum cytokines (MSD and O-link Inflammation 96-panel) and duodenal histology was examined pre- and post- challenge. A CeD patient undertook a 6 wk wheat gluten challenge as a positive control.
Results: Surprisingly, avenin induced a significant acute IL-2 elevation in 11/29 (38%) CeD patients (mean 16-fold elevation) and adverse symptoms such as pain, diarrhea and vomiting were induced in 60%, with severity correlated to higher IL-2 elevation. Five IL-2 responders then undertook 6-wk avenin challenge. Activated avenin-specific tetramer+ effector memory CD4+ T cells were increased on day 6. Interestingly, after 6 wks of avenin, these had returned to baseline and IL-2 responses after avenin were undetectable; all patients were tolerating avenin without the acute initial symptoms. In the duodenum, a similar frequency of tetramer+ cells were seen at baseline and at 6 wks. Notably, duodenal histology after 6 wks avenin remained normal, in contrast to significant deterioration in the wheat challenged patient. Serum inflammatory cytokines were not elevated by avenin except in one highly symptomatic CeD patient to a similar degree as the wheat challenged patient.
Conclusion: Purified avenin induces acute symptoms and T-cell responses in a subset of “sensitive” CeD patients. Reassuringly, our findings suggest that in most CeD patients oats is unable to sustain a pathogenic immune response above the threshold required for mucosal deterioration, in contrast to wheat gluten. These findings help resolve the discrepancy between clinical oats safety and oats immunity in CeD.