Transfusion of platelet concentrates cryopreserved with ThromboSol plus low‐dose dimethylsulphoxide in patients with severe thrombocytopenia: a pilot study

We have recently reported the possibility of supporting the phase of severe thrombocytopenia after high‐dose chemotherapy (HDC) and stem cell transplantation using 5% dimethylsulphoxide (DMSO)‐cryopreserved autologous platelet concentrates (PCs). The aim of the present study was to evaluate the therapeutic potential of ThromboSol (a recently developed platelet storage solution) plus PCs cryopreserved in 2% DMSO in patients undergoing myeloablative chemotherapy and autologous transplantation. PCs were collected from 14 women with breast cancer by a single plateletapheresis and cryopreserved in ThromboSol/2% DMSO by either direct insertion in a −80°C freezer or in liquid nitrogen after computer‐controlled rate (CR) freezing. When required, PCs were thawed, centrifuged to remove the cryoprotectants and transfused. In vitro studies on thawed platelets showed loss of epitopes of surface glycoproteins and a marked reduction of functional activity compared with fresh platelets. Transfusion of CR‐frozen PCs was associated with a mean 1 h corrected count increment (CCI) of 9.2 ± 5.4 × 109/l and only one allogeneic PC was required in this group. In contrast, six out of seven patients required additional allogeneic transfusions in the −80°C group (CCI = 2.7 ± 1.4 × 109/l). ThromboSol‐treated PCs have the ability to overcome thrombocytopenia if processed by a CR freezing protocol, but appear ineffective when frozen by direct placing at −80°C.