Immediate variations in high-dimensional circulating immune cells following pancreatectomy.

Objectives: Despite advancements in surgical techniques and perioperative care, pancreatic surgery remains a high-risk procedure with significant morbidity and mortality. Furthermore, understanding its impact on the immune system is essential for designing strategies that interact with it. The aim of this study was to elucidate the immunomodulation that occurs following pancreatectomy. Methods: Patients were recruited for the IMMUNOPANC trial (NCT03978702). We performed mass cytometry to analyse the circulating immune subpopulations and integrated the data using the hierarchical-stochastic neighbour embedding clustering analysis and Stabl algorithm. Results: Among the enrolled 39 patients, 33 (84.5%) had undergone pancreatectomy for neoplasia including 13 (39%) with pancreatic ductal adenocarcinoma. Twelve (32%) patients developed pancreatic fistula with a 90-day mortality rate of 2.5%. We phenotyped 156 samples and observed a significant increase in myeloid cells (26% vs. 34%, Conclusion: This study presents the first analysis of peripheral immune system trajectories following pancreatic surgery. Understanding these dynamics would facilitate the restoration of postoperative immunity, which is potentially crucial for recovery.