| Class I Antigens | Class II Antigens | |||||
|---|---|---|---|---|---|---|
| Stem Cell Source | HLA A | HLA B | HLA C | HLA DRB1 | HLA DQB1; HLA DPB1; HLA DRB3,4,5 | |
| Matched siblingd BM/PBSCs | Antigen or allele | Antigen or allele | Optional | Allele | N/A | |
| Mismatched sibling/other related-donore BM/PBSCs | Allele | Allele | Allele | Allele | Recommended | |
| Unrelated-donor BM/PBSCs | Allele | Allele | Allele | Allele | Recommended | |
| Unrelated-donor cord blood | Antigen (allele recommended) | Antigen (allele recommended) | Allele recommended | Allele | N/A | |
BM = bone marrow; N/A = not applicable; PBSCs = peripheral blood stem cells.
aHLA antigen: A serologically defined, low-resolution method of defining an HLA protein. Differs from allele-level typing at least 40% of the time. Designated by the first two numbers (i.e., for HLA B 35:01, the antigen is HLA B 35).
bHLA allele: A higher-resolution method of defining unique HLA proteins by typing their gene through sequencing or other DNA-based methods that detect unique differences. Designated by at least four numbers (i.e., for HLA B 35:01, 35 is the antigen and 01 is the allele).
cConsensus recommendations for HLA typing, including extended class II typing of mismatched donors, have been published by the National Cancer Institute/National Heart, Lung, and Blood Institute–sponsored Blood and Marrow Transplant Clinical Trials Network.[5]
dSiblings need confirmation that they have fully matched haplotypes with no crossovers in the A to DRB1 region. If parental typing is performed and haplotypes are established, antigen-level typing of class I is adequate. With no parental haplotypes, allele-level typing of eight alleles is recommended.
eParents, cousins, or other family members, with a phenotypic match or near-complete HLA match.
From: Pediatric Allogeneic Hematopoietic Stem Cell Transplant (PDQ®)
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