Flow cytometric platelet cross-matching to predict platelet transfusion in acute leukemia.

A great variety of patient- and product-related factors influence the outcome of platelet transfusions. Our study assessed the predictive value of a flow cytometric platelet cross match test for the outcome of HLA matched and unmatched platelet transfusions in patients with acute leukemia. Thirty nine patients (26 adults and 13 children) received 60 ABO compatible apheresis platelet unites ranging from 1 to 4 per patient (mean = 1.54; median = 2). We performed flowcytometric platelet cross-matching, HLA Class I typing by sequence-specific primer (SSP) for patients and complement-dependent cytotoxicity (CDC) for donors and screening of HLA Class I antibodies by ELISA. Effectiveness of platelet transfusion was evaluated using the corrected count increment which was calculated at 60 min and 18- to 24-h posttransfusion. Multivariate analysis was performed to detect which variable can predict transfusion response more than others. Cross-matched platelet transfusions associated with good response in 51.4% of transfusion events in adults and 73.3% in children. The noncrossmatched platelet transfusions associated with poor response in 83.3% in adults and 100% in children (P-values 0.143, 0.041, respectively). In the presence of clinical factors or HLA alloimmunization in adults, cross-matched platelets were associated with good response in 29.6 and 22.2% respectively. In children this occurred in 81.8 and 66.7%, respectively. In presence or absence of HLA matching, flow cytometry platelet cross-matching was the most predictor for transfusion response (P = 0.05). Because of the difficulties to find frequent HLA matched donors for acute leukemia patients; flow cytometric platelet cross-matching may provide the most useful way for selecting donors. It is useful even in the presence of alloimunization in children.