What does HLA matched mean?
The short answer is: HLA match = immunologic match. The HLA markers on the surface of cells are what allows the body to recognize that these cells are its own (“self”) or somebody else (“non-self”). Usually we test for HLA in three classes: HLA-A, HLA-B, and HLA-DR, but there are additional surface markers which are not tested for. Each person has two possible inherited types in each of these classes, which are designated by numbers such as HLA-A4, A8 HLA-B27, B19 HLA- DR 1, 11. When all 6 of these are identical between a pair of siblings, they probably inherited all the same immunologic markers from their parents, and their cells cannot be distiguished as different by the immune system. This is the ideal set-up for a bone marrow donor and host: HLA-matched siblings. Any mismatch in the HLA types of two siblings means that they inherited different types from their parents, and that would not be a good set-up for bone marrow transplant. Finally, HLA-matching of unrelated people can be d
