INIGMA multicenter study report. Analysis of immune cells draining from the abdominal cavity as a novel tool to early predict abdominal clinical events

“INIGMA- International Network for Intestinal Graft Monitoring and Analysis” project is a multicenter study started in 2015. Previously, we demonstrated that abdominal drainage fluid collected after intestinal transplant (ITx) contains immune cells trafficking from the implanted intestine, and kinetics of immune cell composition, (mainly neutrophilic shift), correlated with the appearance of future clinical events (rejection, infection, or other abdominal events). Aim: To present a follow-up of our multicenter study, focused on the analysis of draining cell composition and their correlation with clinical follow-up to validate a new non-invasive method predictive to predict the development of abdominal complications after the first post-operational days. Material and Methods: this prospective observational study started in 2008 by Favaloro Foundation University Hospital, Argentina and turned into a multicenter study from 2015 to 2023 (involving Favaloro Foundation University Hospital, Argentina; University of Gothenburg, Sweden; University of Leuven, Belgium and La Paz University Hospital, Spain). The complete leukocytes and differential count of cell composition of the abdominal draining fluid and blood collected during the first post-op days was analyzed by differential cell counter and was correlated with the clinical outcome. Results: a total of 41 patients (pts) with complete biochemical and clinical information were enrolled by 3 of the 4 centers (Table 1). Blood samples showed a predominance of neutrophils and marked leukopenia, independently of the age, immunosuppressive protocol used, and clinical event reported. The draining cell composition showed neutrophilic predominance shifting then to a lymphocytic content. When a new shift to a neutrophil dominant content is observed in the drainage, it anticipates the development of a clinical event in the peritoneal cavity (27/41 pts; p<0,0001). Table 2 summarizes the association between neutrophils and clinical events. Sensitivity=90%; Specificity=90%; PPV=90%, NPV=82%. Conclusion: this follow-up study, validates our preliminary results; suggesting that abdominal clinical events can be early predicted after ITx by a simple analysis of the changes in the drainage cell composition, particularly when a shift to a neutrophilic dominance is registered. Thus, cell counts from the drainage should be included as part of the daily evaluation of pts receiving an ITx. We encourage the international centers of apply to participle in this multicenter study at the IRTA. Table 1. Characteristic of patientsCR, chronic rejection; IR, immunosuppressive regimen; Ind, Induction; Man, maintenance; Simul, Simulect; Alemt., Alemtuzumab; SBS, short bowel syndrome; Tx, transplant; TAC, tacrolimus; Sir, sirolimus; St, steroids; MMF, mycophenolate mofetil; Ritux, rituximab. Spleen pres.: Spleen preservation. Re-Tx: re-transplantation. Table 2. Association of neutrophils appearance and clinical events