HLA Antigenic and Haplotype Frequencies Estimated in Hematopoietic Progenitor Cell Donors From Argentina

Background. Hematopoietic progenitor cell transplantation is considered a standard-of-care treatment for defined hematological and non-hematological conditions affecting bone marrow-derived cells. Methods. Patients and potential donors are HLA typed for their HLA-A, -B, -C, -DRB1, and -DQB1 alleles. The best allogeneic donor is one for which each allele matches the patient at HLA-A, -B, -C, and -DRB1 (8/8). For patients with no related donor, the transplant physician will start a search for unrelated donors. The search is performed through a local registry and often includes the search for donors worldwide. The Argentinean HPC Donors Registry was established in 2003. Our National HPC Donor Registry has already typed more than 31,000 donors for HLA-A, -B, and -DR. Results. We present the analysis of HLA frequencies and haplotypes estimates for the subset of our donor database that is additionally typed for HLA-C. We analyzed HLA data from 2657 donors. Antigen and haplotype frequencies were estimated through the use of expectation maximization. Conclusions. Our analysis showed for the first time the antigenic HLA frequency distribution from HPC donors in Argentina. Knowing haplotype frequencies in our population will help us to select potential donors for high-resolution typing for the patients.