HLA Low-Resolution Genotyping for Hematopoietic Stem Cell Transplantation

Hemopoietic stem cell transplantation from a fully matched sibling donor has been successfully carried out since the mid-1960s. Unfortunately only a third of potential transplant recipients have a fully matched sibling. In addition in the early 1990s it became apparent that the serological tissue typing methods developed for sibling pairs were imprecise when assessing unrelated donors. Molecular techniques capable of discrimination between more than 1500 HLA class I and class II alleles were therefore developed (1 ). Currently no single method is capable of offering genotyping to the allelic level for all possible heterozygous HLA combinations; it is common to combine more than one method to achieve allelic typing or confirm homozygosity.