Influence of red blood cell transfusion on CD4+ T-helper cells immune response in patients undergoing cardiac surgery

Both surgical insult and red blood cell transfusion (RBCT) induce alterations in type-1/type-2, CD4T-helper cell balance. This study was aimed to determine the influence of RBCT on Th1 and Th2 function immune response in cardiac surgery patients.

Three blood samples were prospectively drawn from 81 cardiac surgery patients with cardiopulmonary bypass (CPB): preoperatively (preOP), during CPB, before RBCT (intraOP), and on postoperative day 1 (postOP). Immune response was assessed by flow cytometry measurement of the proportion of CD4(+)T-helper cells producing tumor necrosis factor (TNF)-α [Th1 response] and interleukin (IL)-10 [Th2 response].

Sixty-two patients were transfused (3.4 ± 2.3 units/patient), whereas 19 did not. Both groups were homogeneous, both at baseline and during surgery, regarding multiple perioperative clinical and laboratory variables, but postoperative blood loss and transfused RBC units were significantly higher in transfused versus nontransfused patients. In contrast, preoperative hemoglobin was significantly higher in nontransfused patients. CD4(+)T-helper cells significantly decreased in both groups of patients from preOP to intraOP 1 and from intraOP to postOP. In nontransfused patients, there were no significant changes in CD4(+)T-helper cells expressing TNFα or IL-10 among different sampling times. In contrast, RBCT resulted in a significant increment in Th2 response from intraOP to postOP (P=0.01), without affecting Th1 response.

RBCT, but not surgery or CPB, induces a shift of the Th1/Th2 balance toward Th2 dominance.