RESUMEN
Matching for HLA at the allele level is crucial for stem cell transplantation. The golden standard approach for allele definition of full gene polymorphism, the so-called high-resolution HLA typing, is sequence-based typing (SBT). Although the majority of the polymorphism for class I is located in exons 2 and 3 and for class II in exon 2, for allele definition it is necessary to unravel the complete coding and intron sequences leading to an ultrahigh HLA typing resolution at the allele level, i.e., a full-length gene polymorphism identification.This chapter describes our recently developed SBT method for HLA-A, -B, -C, and -DQB1, that is based on full-length hemizygous Sanger sequencing of the alleles, separated by group-specific amplification using the low-resolution typing result as reference starting point. Group-specific amplification has already been established for DRB. This method enables a cost-efficient, user-friendly SBT approach resulting in a timely unambiguous HLA typing to an ultrahigh resolution level with minimal hands-on time.