- Donors: Related donor who is human leukocyte antigen (HLA) genotypically identical at least at one haplotype and may be genotypically or phenotypically identical for serological typing for HLA-A, B, -C, and at the allele level for -DRB1 and -DQB1; related donors must be a match or a single allele mismatch at HLA-A, B, and C (at highest resolution available at the time of donor selection) and matched at DRB1 and DQB1 by deoxyribonucleic acid (DNA) typing