Detection of a rare Caucasoid HLA-DRB1*0337 in a Taiwanese bone marrow donor using sequence-based typing method.

We here describe the identification of HLA-DRB1*0337, using sequence-based typing (SBT) method, in a Taiwanese bone marrow donor intrigued by a casual curiosity on the donor's racial background. On high-resolution sequence-specific primer (SSP) typing we observed misleading reaction patterns due to similarity of DNA sequences in the exon 2 of DRB1*0301, *0317, *0337 and *1139. When encountering rare alleles in HLA typing, it is important to pay extra attentions to avoid pitfalls and shortcomings of SSP typing kits routinely used and bear in mind that constant up-dating of high-resolution SSP typing kits to be able to distinguish newly reported alleles. SBT may be considered as a back-up HLA typing method to confirm rare alleles.