- DONOR: Cord blood (CB) donor selection will be based on institutional guidelines and in general should be selected to optimize both human leukocyte antigen (HLA) match and cell dose; additionally, CB grafts shall consist of one or two CB donors based on, but not exclusively determined by, cell dose (total nucleated cell [TNC]/kg and CD34/kg), HLA matching and disease status and indication for transplant; attending preference will be allowed for single versus double unit as well as the degree of mismatching based on patient specific factors, as long as the following minimum criteria are met: