Search

The transplantation of hematopoietic stem cells (HSC) from a healthy individual can be the only curative therapy for patients with malignant or non-malignant diseases of the blood system. Current requirements for the transplantation of HSC demand to match the five human leucocyte antigen (HLA) loci A, B, C, DRB1 and DQB1 on allele level between patient and donor. Given the heterogeneous i.e. non-allele level HLA data usually available in the files of big unrelated donor registries, the estimation of five locus haplotype frequencies in allele level resolution is highly desirable in order to be used in various applications improving patient care. A tailored and methodically extended implementation of the frequently employed expectation-maximization algorithm is needed to achieve this aim due to the complexity introduced by ambiguous or missing HLA data found in the daily practice of unrelated donor search. The HLA haplotype frequencies achieved with this new methodology are validated against comparable haplotype frequencies published in the literature. The haplotype frequencies of German donors presented here are more precise when used for predicting the degree of HLA compatibility between donors and patients.