Allogeneic transfusion and infection: economic and clinical implications.

An increased incidence of postoperative infection and risk of cancer recurrence in patients who have received allogeneic blood transfusions suggests that such transfusions may be associated with clinically significant immunomodulatory effects. Allogeneic transfusion increase humoral immunity and decrease cell-mediated immunity. The mechanism of allogeneic transfusion-induced immunomodulation may involve altered cytokine regulation with a shift toward a type-2 (Th2) immune response. In patients undergoing hip replacement or spine surgery, the postoperative infection rate with allogeneic blood transfusion appears to be 7- to 10-fold higher than with autologous blood or no transfusion. The occurrence of postoperative infection is largely abrogated through the use of autologous or leukocyte-depleted blood. In our orthopedic surgery patients, use of allogeneic blood was associated with a significantly increased length of hospital stay, resource consumption, and attendant hospital charges. Allogeneic, but not autologous, blood transfusion were associated in a dose-dependent manner with longer hospital stays and higher costs. Multiple linear regression analyses demonstrated that the number of units of allogeneic blood transfused, rather than surgeon and type of surgery, was the most statistically significant predictor of length of stay and hospital charges. Using data reported in the literature, we estimate that the death rate from allogeneic transfusion-related postoperative infection and cancer recurrence combined (215 deaths with 1% causality to 21,500 with 100% causality) may exceed the death rate due to all other transfusion risks combined. Improved clinical outcomes may result from techniques that minimize allogeneic blood use or its immunologic effects (e.g., autologous transfusion or other blood-sparing approaches in surgery, leukodepletion of allogeneic blood, and the use of growth factors [eg, epoetin alfa]).