- Patients must have a partially human leukocyte antigen (HLA)-matched UCB unit. Unit must be HLA-matched minimally at 4 of 6 HLA-A and B (at intermediate resolution by molecular typing) and DRB1 (at high resolution by molecular typing) loci with the patient. The unit must deliver a pre-cryopreserved nucleated cell dose of at least 2.5 x 10^7 per kilogram.