- DONORS will be a HLA-identical sibling or HLA-matched unrelated donor; unrelated donors are required to be matched by high resolution allele level typing for HLA-A, B, C and DRB1 and intermediate resolution Sequence Specific Oligonucleotide Probes (SSOP), identifying alleles in groups of related families historically defined as antigens for DQB1; an unrelated donor is considered matched if patient and donor share HLA-A, B, C alleles with identical sequences at exons 2 and 3, DRB1 alleles with identical sequences at exon 2, and DQB1 results that include the same allele groups