Abstract
Refractoriness to platelet transfusions is considered one of the major obstacles in treating patients with hematological disorders. Although various transfusion procedures have been tried to prevent HLA alloimmunization, some patients still develop HLA and/or HPA antibodies and become refractory to platelet transfusions. We investigated the AHG-LCT, MPHA, LIFT and FlowPRA methods for detecting HLA antibodies and MPHA using chloroquine-treated platelets for HPA antibodies to analyze immunological factors in platelet transfusion-refractory (PTR) patients. Results showed that HLA antibodies were detected in 55 patients, HPA antibodies in 2 and both HLA and HPA antibodies in 2 patients. HLA-A and -B-compatible platelet transfusions were successful in boosting platelet levels in 27 of the patients. Nine patients developed not only HLA-A and/or -B antibodies but also HLA-C antibodies and became refractory to HLA-A and -B-compatible platelet transfusions. Matching of the HLA-C antigens was required in these patients to ensure the effectiveness of platelet transfusions. In some patients, ABH incompatibility reduced the effectiveness of transfusions. In these patients, platelet crossmatching was useful for predicting platelet survival. Of the 68 ABH-incompatible transfusions evaluated at 24 hours post-transfusion, 20 with positive crossmatches had corrected platelet count increments of 3.1±4.1 (×109)/L. In contrast, 48 transfusions with negative crossmatches had corrected platelet count increments of 18.1±7.6 (×109)/L. Other weak HLA antibodies in ten patients were not detected by the conventional methods but were detected by the FlowPRA method. Owing to screening and crossmatch tests, platelet transfusion efficacy was improved in 59 immunological PTR patients.
