Changes in lymphocyte subsets after cardiac surgery in children

Abstract

Children undergoing cardiopulmonary bypass (CPB) operations have an increased risk of developing severe infections. Impairment of the immune system may contribute to the development of sequelae such as capillary leaks, pulmonary dysfunction and auto-immune reactions. The objective of this study was to investigate the impact of cardiac surgery with CPB on the immune system of infants and young children. We conducted a prospective study to investigate the changes in circulating lymphocyte subpopulations in a sample of 21 consecutive infants and young children undergoing cardiac surgery for congenital heart disease. The following statistically significant ( P<0.05) results were obtained: leucocyte counts rose 6 h after surgery due to the increase in neutrophils. Absolute T-cell number and absolute T-helper cell number decreased within 24 h after CPB. The proportion of T-cells expressing the T-cell receptor gammadelta as well as natural killer cells increased during CPB. In contrast, the proportion of T-cells expressing activation markers (CD25, CD45R0) decreased within 24 h after CPB, as did the number of cells expressing adhesion molecules (CD11b and ICAM).

Conclusion: during cardiac surgery with cardiopulmonary bypass, absolute natural killer cell counts increase while T-cells decrease, presumably due to an extravasation or adhesion of activated T-cells. The relevance of this finding regarding the risk of infection is discussed.