Flow cytometric analysis of total lymphocyte apoptosis, a potential prognostic assay for sepsis

Intensive research has identified the number of apoptotic lymphocytes as a reliable marker of sepsis. This study determined whether the number of apoptotic lymphocytes can be used as a prognostic marker of patients with severe sepsis. A prospective study comprising 30 patients was conductod with severe sepsis grouped according to 14-day mortality of 15 patients who each were survivors and nonsurvivors. The number of apoptotic lymphocytes was calculated using flow cytometry with a PerCP-labeled anti-CD45 monoclonal antibody, FITC-labeled Annexin V, and propidium iodide. Subjects characteristics were recorded, and the number of apoptotic lymphocytes was calculated. The mean percentages of apoptotic lymphocytes in the survivor and nonsurvivor groups were significantly different (0.992% [SD = 0.44%] and 1.5853% [SD = 0.57%], respectively, p = 0.004). The cutoff value of apoptotic lymphocytes for predicting prognosis was 0.97%, AuC = 0.791 (CI 95% 0.631-0.951), 86.7% sensitivity, and 60% specificity. Kaplan-Meier analysis yielded a hazard ratio of 0.182 (95% CI 0.041-0.814, p = 0.026). These data provide compelling evidence that the number of apoptotic lymphocytes in patients with severe sepsis predicts nonsurvivors and that this cutoff value can be used manage patients with severe sepsis.