Changes in T cell metabolism in post-cardiac arrest patients
Hurley, Meredith Alden
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Objective: The survival rates for cardiac arrest patients to hospital discharge are very low. Post-arrest patients have an immune response and usually a period of immunosuppression. When CD3+ T cells activate, they switch from primarily relying on aerobic metabolism to primarily relying on anaerobic metabolism. The goal of this study is to characterize the immune system of post-cardiac arrest patients. The specific objectives are (1) to determine the time period after the occurrence of a cardiac arrest that a patient acquires an infection, (2) to identify the most common types of infections in post-arrest patients, (3) to compare in vitro the cellular oxygen consumption of immune cells post-cardiac arrest with healthy controls, and (4) to compare cell proliferation and ATP production of immune cells post-cardiac arrest with healthy controls. Methods: We conducted a retrospective chart review of 170 cardiac arrest patients (Beth Israel Deaconess Medical Center) who had return of spontaneous circulation. We measured oxygen consumption rates of peripheral blood mononuclear cells (PBMCs) in cardiac arrest patients and healthy controls. We also measured cell proliferation and ATP production of CD3+ T cells in cardiac arrest patients and healthy controls. Results: Of the 170 cardiac arrest patients we reviewed, 42% had at least one incidence of infection. The length of time from cardiac arrest to first positive culture was 4 days, with pneumonia and urinary tract infections the most common diagnoses. The PBMCs of cardiac arrest patients showed a significant decrease in oxygen consumption post arrest compared with healthy controls. When thiamine was added to the PBMC samples of cardiac arrest patients, there was a significant increase in oxygen consumption from baseline. There was no significant difference in cell proliferation or ATP production of CD3+ T cells between the two groups of post-cardiac arrest patients and healthy controls. Conclusion: Many patients suffer from infections post-cardiac arrest, and future research is needed on this subject. Our data support the hypothesis that post-arrest patients have a period of hyperimmune response followed by a period of immunosuppression.