Typing of potential and selected donors for transplant: methodology and resolution

The goal was to establish the best typing techniques and strategies for donors selected as potential donors for a specific patient. Complete sequence of exons 2 and 3 for class I and exon 2 for class II molecules by sequencing-based typing was deemed the best technique in reducing problems with ambiguities and null alleles as well as the possibility to establish a completely automated system. Focusing on multiple approaches for typing was regarded as a better strategy than continued usage of serological methods although the latter technique was still considered to be useful by some for detection of null alleles. The patient and finally the selected donor, including the back-up donor, should be typed for at the highest level and typing ambiguities should be resolved. In very difficult cases, race, haplotype information and allele frequency in the population should help to decide whether or not to resolve the ambiguity. Cellular techniques such as the cytotoxic T lymphocyte precursor test may help to choose between single class I mismatched donors in experienced laboratories only.