Abstract

BACKGROUND Recent data suggest that most reactions to platelets are caused by white cell (WBC)-derived cytokines that accumulate in the plasma portion of the component during storage. On the basis of this theory, the effectiveness of two interventions to prevent reactions, poststorage WBC reduction and plasma depletion, were compared. STUDY DESIGN A multiple crossover design was used, in which platelet components for transfusion to a patient randomly were WBC reduced after storage, or the plasma supernatant was removed. Adults >17 years of age, with a hematologic disease requiring platelet transfusion support, were eligible for the study. Patients were assessed for signs and symptoms characteristic of a reaction during, immediately after, and 1 hour after transfusion. Reactions were graded as mild, moderate, or severe. Interleukin 6 levels were also measured in the transfused platelet components. RESULTS There were 380 analyzable platelet transfusions to 30 patients. The frequency of reactions was 25.8 percent (48/186) in the transfusions of poststorage WBC-reduced platelets and 17.0 percent (33/194) in the transfusions of plasma-depleted platelets (p<0.008). The severity of the reaction was graded by the patient. Severe reactions occurred more frequently in connection with poststorage WBC-reduced platelets than with plasma-depleted platelets: 33.4 percent (16/48) versus 18.2 percent (6/33), respectively (p = 0.048). Regression analysis identified interleukin 6 as the most significant of the evaluated factors in its correlation with the risk of reaction. CONCLUSION Plasma removal is more effective than poststorage WBC reduction in preventing reactions, especially severe reactions to platelets.

Abstract

Patients undergoing induction chemotherapy for acute leukaemia often become refractory to platelet transfusions. Increased clearance of transfused platelets due to alloimmune destruction has been identified as one of the primary mechanisms contributing to this refractory state. We performed a double-blind randomized trial to determine whether the administration of anti-D to Rh-positive individuals could prevent the refractory state and improve post-transfusion platelet response. Rh-positive patients with acute leukaemia undergoing induction chemotherapy and requiring platelet transfusions were allocated to weekly intravenous anti-D (20 micrograms/kg) or placebo. Platelets and red cell concentrates were administered according to standardized transfusion guidelines. Outcome measures included platelet transfusion utilization, red cell utilization, platelet recovery 18-24 h post-infusion, and the percentage of patients refractory to platelet transfusion. There were 43 patients studied: 21 received anti-D and 22 saline placebo. The mean number of platelet concentrates required per day of observation was 0.59 (SD 0.22) in the anti-D group and 0.61 (SD 0.22) in the placebo group, P = 0.86. No difference was detected between groups in terms of platelet recovery post-infusion, refractoriness to platelet transfusion or frequency of infection (P = 0.97). Red cell concentrate utilization was significantly increased in the anti-D group compared to the placebo group, 0.58 units per day versus 0.37 units per day respectively, P = 0.005. We conclude that the use of anti-D did not improve post-transfusion platelet response in Rh positive patients with acute leukaemia, but did result in an increased need for red cell transfusion.