- Must have an unrelated adult donor (marrow or PBSC) who is matched at least seven of eight HLA alleles (A, B, C, DRB1; the mismatch can be at an allele or antigen level)* or an unrelated cord blood unit that is matched at least seven of eight loci (A, B and C antigen level-DRB1 allele level) and provides a minimum pre-cryopreservation TNC dose of 7.5 x 107 TNC/kg recipient weight. Mismatches at the DRB1 locus may be at an antigen or allele level.