“…Since RBCs, white blood cells (WBCs), platelets (PLTs), and plasma differ in size and density, they can be efficiently separated by density gradient centrifugation or apheresis, and both have been applied successfully. [6][7][8][9] The critical variables for the success of RBC depletion of BM are recovery of CD341 "stem cells," which are contained within the mononuclear cell (MNC) population and, when performed in the context of ABO majorincompatible BMT, near-qualitative removal of RBCs to values below 0.5 mL/kg body weight of the recipient. Similar processing of whole blood, buffy coats (BCs), and occasionally, apheresis products generally also aims for best-possible RBC depletion while maximally recovering MNCs.…”