Safety and efficacy of cryopreserved autologous platelet concentrates in HLA-alloimmunized patients with hematologic malignancies

BACKGROUND Curative chemotherapy approaches in patients with malignancies and platelet (PLT) transfusion refractoriness due to alloimmunization may be hampered by the lack of suitable PLT donors. For these patients, transfusion of cryopreserved autologous PLTs is an option, but is time- and resource-consuming. We aimed at further simplifying this process. STUDY DESIGN AND METHODS A retrospective single-center analysis was conducted on the transfusion of cryopreserved autologous PLTs in nine female alloimmunized, PLT transfusion–refractory patients treated for acute leukemia (n = 8) and non-Hodgkin's lymphoma (n = 1). No additional processing was used before transfusion, and most notably, washing and centrifugation steps were omitted. Clinical efficacy and safety, as well as a flow cytometric assessment of structural and functional PLT changes, were analyzed. RESULTS A total of 40 autologous PLT concentrates were thawed at bedside and transfused a median of 32 (range, 9 to 994) days after cryopreservation. No major bleeds and no severe dimethyl sulfoxide toxicity were observed. The median PLT count increments did not differ 1 and 18 to 24 hours after transfusion and reached 6 × 109/L (interquartile range [IQR], 3 × 109−7.5 × 109/L) and 6 × 109/L (IQR, 2.5 × 109−9.5 × 109/L), respectively. Cryopreservation resulted in partial activation of one-third of the PLTs. In vitro stimulation with strong agonists induced additional full activation of cryopreserved PLTs: median, 55% (IQR, 42%-60%) after thrombin and 39% (IQR, 36%-39%) after convulxin. CONCLUSION The transfusion of cryopreserved autologous PLTs is feasible and safe. Despite the cryopreservation process, PLT functionality is partially maintained.