HLA system, tissue typing and crossmatching
HLA class I and II structure, expression and inheritance, sibling match probabilities, how sensitisation happens, and how HLA typing, single-antigen bead antibody testing, cPRA and the CDC, flow and virtual crossmatches decide solid organ and stem cell transplant compatibility.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- HLA (the human MHC) sits on chromosome 6p21. It presents peptides to T cells, and is the most polymorphic system in the genome, which is why it dominates transplant rejection.
- Class I (A, B, C) presents intracellular peptides to CD8 T cells and is on all nucleated cells. Class II (DR, DQ, DP) presents extracellular peptides to CD4 T cells and is on antigen-presenting cells.
- Genes are inherited as haplotypes, one from each parent, and expressed co-dominantly.
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Sources
- Janeway's Immunobiology (10th ed.)W. W. Norton (Murphy and Weaver), 2022
- Clinical guidelines for organ transplantation from deceased donorsAU/NZTransplantation Society of Australia and New Zealand (TSANZ)
- OrganMatch: national organ matching systemAU/NZAustralian Red Cross Lifeblood and Organ and Tissue Authority
- Consensus guidelines on the testing and clinical management issues associated with HLA and non-HLA antibodies in transplantationTransplantation (Tait et al.), 2013
- HLA-B*5701 screening for hypersensitivity to abacavir (PREDICT-1)AU/NZNew England Journal of Medicine (Mallal et al., 2008;358:568-79), 2008
- Last updated
- 14 November 2026
What changed
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