An evaluation of platelet transfusion response using HLA crossmatch-compatible donors in patients with platelet refractoriness

Abstract

Background: Majority of immune-mediated platelet refractoriness is caused by HLA alloimmunization and can be effectively managed by HLA-matched platelet transfusions. However, HLA class I-typed large-sized donor registry has not been well established in Korea. We evaluated the effectiveness of platelet transfusion using HLA crossmatch-compatible donors without HLA typing. Methods: Sixteen patients showing platelet refractoriness to random donor platelets (1 hr corrected count increment [CCI] <7,500/μL/m2) and HLA alloimmunization (class I panel reactive antibody >60%) were crossmatched with 78 platelet apheresis-eligible donors using National Institute of Health (NIH) and anti-human globulin (AHG) lymphocytotoxicity methods. NIH negative/AHG negative and NIH negative/AHG positive donors were selected as best and second choice donors, respectively. Results: Eleven patients (11/16, 69%) could find NIH-crossmatch negative donors and 27 donors (27/78, 35%) belonged to the best donors. To 8 patients, 32 apheresis platelet products from 19 donors were transfused. The mean 1 hr and 24 hr CCI values from the best donors were significantly higher than those from random donors (17,893 vs 2,358, P=0.003; 8,292 vs -614, P<0.001), whereas such differences were not observed for those from the second choice donors. Platelet storage time was inversely correlated with CCI values and platelets stored ≤10 hr after collection gave significantly higher CCI values. Neither ABO match nor donor status (related vs unrelated) affected the transfusion effectiveness. Conclusions: Effective post-transfusion platelet increment using HLA crossmatch-compatible donors was attained in patients with platelet refractoriness due to HLA antibodies, and this method can be used effectively where HLA-typed platelet donor registry is not available.