Transfusion-related immunomodulation: gamma irradiation alters the effects of leukoreduction on alloimmunization
BACKGROUND Adverse events following blood transfusion include allosensitization and generalized immunosuppression, collectively referred to as transfusion-related immune modulation. We evaluated the immunological effects of red blood cell (RBC) and platelet transfusions on alloantibody responses and on immunoregulatory cells in nonimmunosuppressed patients undergoing cardiovascular surgery. STUDY DESIGN AND METHODS Patients were randomized to receive standard unmodified (STD), leukoreduced (LR), or leukoreduced and gamma-irradiated (LRgamma) RBCs. Patients received only apheresis platelets that were in-process LR and were gamma-irradiated for the third arm. Nontransfused patients served as controls for the effects of surgery itself on immunologic changes. Antibodies to HLA were assessed with use of solid-phase assays. The effects of transfusion on adaptive and innate immunity were evaluated by assessing T regulatory cells (Tregs) and invariant natural killer T (iNKT) cells. RESULTS LR of blood products reduced the development of human leukocyte antigen (HLA) alloantibodies, but only in patients without preexisting HLA antibodies. However, if LR blood products were gamma-irradiated, HLA antibody production was not reduced. Compared to nontransfused patients, recipients of STD or LR transfusions showed a significant increase in CD4+CD25(hi) T cells expressing FoxP3 or CTLA4 and also of iNKT cells producing interleukin-4. In contrast, recipients of LRgamma blood products showed markedly lower increases in all three cellular assays. CONCLUSION LR decreased HLA alloantibody production in naive recipients, but did not reduce the immunosuppressive effects of transfusion. LRgamma reduced immunosuppression and was not associated with decreased HLA alloantibody production.
Immunomodulatory effects of transfusion
Blood. 2015;126((23)): Abstract No. 1144.
Blood transfusion is associated with prolonged duration of mechanical ventilation in infants undergoing reparative cardiac surgery
Pediatric Critical Care Medicine. 2011;12((1):):52-6.
OBJECTIVE Perioperative transfusion has adverse effects in adults undergoing cardiac surgery. We sought to investigate whether greater use of blood and blood products might be an independent predictor of prolonged postoperative recovery, indicated by duration of mechanical ventilation (DMV), after reparative infant heart surgery. DESIGN Secondary analysis of prospectively collected data from two randomized trials of hematocrit strategy during cardiopulmonary bypass in infant heart surgery to explore the association of DMV with perioperative transfusion and other variables. SETTING Tertiary pediatric hospital. PATIENTS Two hundred seventy infants undergoing two ventricle corrective cardiac surgery without aortic arch reconstruction. MEASUREMENTS AND MAIN RESULTS In univariable analyses, longer DMV was associated with younger age and lower weight at surgery, diagnostic group, and higher intraoperative and postoperative blood product transfusion (each p < .001). In multivariable proportional hazard regression, longer total support time and greater intraoperative and early postoperative blood products per kg were the strongest predictors of longer DMV. Patients in the highest tertile of intraoperative blood products per kg had an instantaneous risk of being extubated approximately half that of patients in the lowest tertile (hazard ratio, 0.51; 95% confidence interval, 0.35, 0.73). Patients who received any blood products on postoperative day 1, compared with those who did not, had a hazard ratio for extubation of 0.65 (95% confidence interval, 0.50, 0.85). CONCLUSIONS In this exploratory secondary analysis of infants undergoing two ventricular repair of congenital heart disease without aortic arch obstruction, greater intraoperative and early postoperative blood transfusion emerged as potential important risk factors for longer DMV. Future prospective clinical trials are needed to determine whether reduction in blood product administration hastens postoperative recovery after infant heart surgery.