Refractoriness to platelet transfusion in the presence of anti-HLA antibodies—reassessing the alloantibody hypothesis

Since platelet products first became routinely available in the 1970s, platelet transfusions have been a mainstay of the treatment of thrombocytopenic patients, decreasing the frequency and severity of bleeding sequelae (1). While the overall clinical goal is to decrease bleeding, the success of a platelet transfusion is often determined by an increase in platelet count post-transfusion [often reported as corrected count increment (CCI)] (2). The CCI may range from a substantial increase in platelet count to no effect at all; in some cases, a decrease in CCI can even be observed post-transfusion.