A European HLA Isolate and Its Implications for HSCT Donor Procurement.

•HLA isolates can be found even in Europe.•The Finnish HLA is illustrated by common European alleles and high HLA homogeneity.•A large proportion of frequent Finnish HLA haplotypes are extremely rare elsewhere.•One-quarter of the Finnish population carries rare HLA haplotypes that are enriched in Finland.•These individuals are more likely to receive a mismatched or domestic hematopoietic stem cell transplant.