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Response of the cellular immune system to cardiopulmonary bypass in vivo
M Misoph1, J Babin-Ebell, S Schwender
1Department of Cardiothoracic Surgery, University Hospital, Würzburg, Germany.
Insights
Cardiopulmonary bypass (CPB) transiently impacts the immune system, causing temporary immunosuppression. This study monitored leukocyte changes during and after coronary artery bypass grafting surgery.
Area of Science:
- Immunology
- Cardiovascular Surgery
Background:
- Cardiopulmonary bypass (CPB) is associated with inflammatory responses.
- Previous research indicates CPB impairs cellular immunity, activating neutrophils and altering lymphocyte subsets.
Purpose of the Study:
- To investigate the in vivo effects of CPB on leukocyte activation.
- To analyze quantitative and qualitative changes in leukocyte populations during and after CPB.
Main Methods:
- Flow cytometry was used to analyze leukocyte populations.
- 27 patients undergoing coronary artery bypass grafting were studied.
- Samples were collected preoperatively, intraoperatively, and postoperatively.
Main Results:
- Leukocyte counts increased significantly during CPB, leading to postoperative leukocytosis.
- Lymphocyte counts initially increased then decreased, primarily due to loss of B and cytotoxic T cells.
- Post-protamine lymphocytopenia was mainly attributed to a decrease in helper T lymphocytes.
- Distinct leukocyte populations showed activation during and after CPB.
Conclusions:
- CPB influences the cellular immune system.
- Immunosuppression due to CPB is detectable but transient.
Abstract:
Cardiopulmonary bypass (CPB) is known to induce an inflammatory response. Previous studies reported an impairment of the cellular immune response with activation of neutrophils and changes in lymphocyte subpopulations. The objective of the present study was to investigate the effect of CPB on leukocyte activation in vivo. In 27 patients undergoing coronary artery bypass grafting, the quantitative and the qualitative response of leukocyte populations to CPB was analysed pre-, intra-, and postoperatively using flow cytometry. A significant increase in leukocyte counts was detected during CPB, resulting in a marked leukocytosis postoperatively. The total number of lymphocytes peaked in the early phase of CPB, followed by a significant decrease, mainly due to a loss in B and cytotoxic T lymphocytes. In contrast, the lymphocytopenia observed 8 h after protamin administration was mainly caused by a drop in the population of helper T lymphocytes. Activation of distinct cell populations could be detected during and following CPB. The results indicate an influence of CPB on the cellular immune system, however an immuno-suppression was detectable only transiently.
