Prognostic significance of lymphocyte apoptosis markers (Annexin V, sFas, and sFasL) in sepsis: a retrospective clinical study

Background Sepsis-associated lymphocyte apoptosis may contribute to immune dysfunction and adverse outcomes. Annexin V binding detects phosphatidylserine externalization, a general feature of early apoptosis that is not specific to Fas-mediated signalling; soluble Fas (sFas) and soluble Fas ligand (sFasL) are more directly related to the Fas/FasL system. Their combined prognostic associations in sepsis merit evaluation. Methods In this reported single-centre observational cohort, 218 adults with Sepsis-3-defined sepsis were included. Annexin V positivity was assessed by flow cytometry and sFas and sFasL by ELISA within 24 h of ICU admission (Day 1), with additional measurements planned on Days 3 and 7 when feasible. The primary endpoint was 28-day all-cause mortality. Results The manuscript reports 75 deaths among 218 patients (34.4%). At Day 1, non-survivors had higher Annexin V-positive lymphocyte percentages (28.7% ± 5.9% versus 14.3% ± 4.2%), sFas (4218 ± 863 versus 2104 ± 612 pg/mL), and sFasL (312 ± 78 versus 164 ± 43 pg/mL); the reported between-group p values were <0.001. The reported adjusted associations and combined-panel AUROC (0.891 versus 0.768 for sequential organ failure assessment) remain exploratory, in-sample estimates pending source-data audit and internal validation. Conclusion Higher admission levels of Annexin V positivity, sFas, and sFasL were associated with 28-day mortality in the reported cohort. The apparent discrimination of the combined panel is hypothesis-generating; prospective, multicentre external validation and assessment of missing longitudinal data are required before clinical implementation or use as a therapeutic monitoring endpoint.