AB107. SOH21AS190. Timing is everything; manipulating the surgery induced immunosuppressive milieu into a therapeutic target

• DOI: 10.21037/map-21-ab107
• Publication Date: 2021-04-21T04:08:20Z
• Authors: Noel Edward Donlon; Maria Davern; Andrew Sheppard; Michael McClean; Sinead Ramjit; Robert Power; Conall Hayes; Hugo Temperley; Ryan Roopnarinesingh; Jarlath Bolger; Waqas Butt; Narayanasamy Ravi; Claire Donohoe; Margaret Dunne; Jacintha OSullivan; John Reynolds; Joanne Lysaght

Background: Immune checkpoint inhibitors (ICIs) are being investigated for their role as an adjunct in the multimodal treatment of oesophageal cancer. The most appropriate time to incorporate ICIs remains unknown. Our study profiles systemic anti-tumour immunity perioperatively help inform optimal timing into current standards care adenocarcinoma (OAC) patients.Methods: Systemic was immunophenotyped pre- and post-oesophagectomy on days 0, 1, 3, 7 week 6 by flow cytometry (n=14). frequency circulating lymphocytes, T cells, cytotoxic helper lymphocytes profiled longitudinally including proportion cell subsets circulation. This also immune expression cells including: PD-1, CTLA-4, TIGIT, TIM-3, LAG-3, PD-L1 PD-L2. Markers immunogenicity (calreticulin, HMGB1 MIC-A/B) were assessed.Results: naïve increased circulation from POD-0 POD-7 (P<0.01) but returned baseline at 6. Effector memory decreased POD7 returning normal Increases activated CD27+ observed (P<0.01), interestingly remaining high a patients that experienced complications. percentage positive peaked POD-1 substantially (P<0.01).Conclusions: We activation checkpoints immediately post-surgery with returns These results suggest such anti-PD-1 may be beneficial maintain prevent exhaustion this population post-surgery.