CCR5Δ32 and HLA allele diversity in bone marrow donors from southern Brazil

Transplantation of stem cells derived from donors with CCR5 Delta 32 homozygous genotype is a potential strategy to achieve both the control of malignant hematological disease as well as sustained remission of the HIV infection, and researchers in different countries are looking for CCR5 Delta 32 homozygous donors to replicate such a 'double- target' strategy. We determined the frequency of the CCR5 Delta 32 variant in a sample of 1,398 bone marrow donors from Rio Grande do Sul State, Brazil. This study also evaluated whether HLA-A, HLA-B and HLA-DRB1 genotypes are homogeneously distributed between CCR5 Delta 32 carriers and non-carriers in a population characterized by a significant genetic admixture. The CCR5 Delta 32 allele frequency was 7.4% (CI0.95 6.4-8.4%), and the frequency of the Delta 32/Delta 32 homozygous genotype was 0.72% (CI0.95 0.34-1.31%). In general, HLA genotypes are homogeneously distributed between CCR5 Delta 32 carriers and non-carriers. Considering the large number of bone marrow donors in Brazil and the high CCR5 Delta 32 allele frequency observed in our study, our results clearly indicate the existence of a considerable amount of potential CCR5 Delta 32 homozygous bone marrow donors in southern Brazil, suggesting that an active search for these donors is not only feasible but an attractive and promising strategy towards effective HIV infection control and treatment.