Creating an HLA-homozygous iPS cell bank for the Brazilian population: Challenges and opportunities

Identifying human leukocyte antigen (HLA) haplotype-homozygous donors for the generation of induced pluripotent stem (iPS) cell lines permits the construction of biobanks immunologically compatible with significant numbers of individuals for use in therapy. However, two questions must be addressed to create such a bank: how many cell lines are necessary to match most of the recipient population and how many people should be tested to find these donors? In Japan and the UK, 50 and 100 distinct HLA-A, -B, and -DRB1 triple-homozygous haplotypes would cover 90% of those populations, respectively. Using data from the Brazilian National Registry of Bone Marrow Donors (REDOME), encompassing 4,017,239 individuals, we identified 1,906 distinct triple-homozygous HLA haplotypes. In Brazil, 559 triple-homozygous cell lines cover 95% of the population, and 3.8 million people would have to be screened. Finally, we show the contribution of the 30 most frequent triple-homozygous HLA haplotypes in Brazil to populations of different countries. •iPS cells from HLA-homozygous donors creates biobanks for cell therapies•Admixture in Brazilian population results in diversified genomes•Our genetic diversity might provide a more globally representative iPS biobank•We show contributions of 30 HLA Brazilian haplotypes to different populations In this article, Campos de Carvalho and colleagues show that, in Brazil, a triple-homozygous cell bank with 559 cell lines covers 95% of the population and requires 3.8 million people to be screened. They also show the contribution of the 30 most frequent triple-homozygous Brazilian HLA haplotypes to populations of different countries.