Changes in T-cell receptor subsets after cardiac surgery in children

T cells are divided into two subsets, alpha beta and gamma delta, according to the T-cell receptor (TCR) expressed. Recent findings indicate that gamm a delta T cells serve as the first defense against microbial pathogens, and represent a link between innate and acquired immunity. We conducted a stud y to investigate the changes in circulating TCR subsets after cardiac surge ry in children. Blood samples from 24 children who underwent cardiac surger y with cardiopulmonary bypass (CPB) were collected serially to analyze TCR subsets by flow cytometry. The alpha beta T cells reached a nadir on postop erative day (POD) 1, but recovered to pre-CPB levels on POD 3. On the other hand, the gamma delta T cells decreased after CPB and did not recover to p re-CPB levels even after POD 7. The alpha beta/gamma delta T-cell ratio was increased after POD 3. In children, gamma delta T cells recover more slowl y than alpha beta T cells after cardiac surgery. These changes in TCR subse ts may contribute to postoperative immunosuppression.