The effect of unmodified or prestorage white cell-reduced allogeneic red cell transfusions on the immune responsiveness in orthopedic surgery patients

BACKGROUND: The immunomodulatory effects of allogeneic blood transfusions h ave been attributed to the white cells (WBCs) present in the cellular blood components transfused to patients. STUDY DESIGN AND METHODS:The effect of the transfusion of allogeneic red ce lls (RBCs) or allogeneic prestorage WBC-reduced RBCs (WBC-reduced RBCs) on host immune responsiveness was evaluated by measuring the lymphocyte subset s and the in-vitro cytokine production in response to phytohemagglutinin st imulation of WBCs of orthopedic surgery patients. Forty-seven patients unde rgoing hip replacement surgery were randomly assigned to receive allogeneic RBCs (n = 17) or WBC-reduced RBCs (n = 14; 99.95% WBC removal). Sixteen pa tients were not transfused. Patient blood samples taken before surgery and on Days 1 and 4 after surgery were tested for complete blood count, lymphoc yte subset analysis, and measurement of cytokine levels. RESULTS: After surgery, the lymphocyte count was significantly decreased in patients transfused with greater than or equal to 3 units of allogeneic RB Cs (2.0 +/- 0.5 vs. 1.3 +/- 0.3 x 10(9)/L; p = 0.017), but not in patients transfused with greater than or equal to 3 units of WBC-reduced RBCs (2.0 /- 0.9 vs. 1.7 +/- 0.8 x 10(9)/L). Compared with preoperative levels, on Da y 4 after surgery, patients transfused with greater than or equal to 3 unit s of allogeneic RBCs also had a decrease in the number of natural killer ce lls (0.07 +/- 0.05 vs. 0.04 +/- 0.03 x 10(9)/L; p = 0.018). Postoperatively , interleukin-2 was decreased in one patient who received WBC-reduced RBCs compared with that in four patients transfused with allogeneic RBCs (p = 0. 32), and eight untransfused patients (p = 0.01). On Day 4, about 70 percent of patients transfused with allogeneic RBCs showed a 20-percent decrease i n the interferon gamma level. CONCLUSION: Taken together, these data support the hypothesis that transfus ion of greater than or equal to 3 units of allogeneic RBCs is associated wi th early postoperative lymphopenia in otherwise healthy individuals undergo ing surgery. These findings were not observed in those individuals transfus ed with RBCs that had undergone prestorage WBC reduction.