Influence of donor–recipient sex on engraftment of normal and leukemia stem cells in xenotransplantation

Immunodeficient mouse models are widely used for the assessment of human normal and leukemic stem cells. Despite the advancements over the years, reproducibility, as well as the differences in the engraftment of human cells in recipient mice remains to be fully resolved. Here, we used various immunodeficient mouse models to characterize the effect of donor–recipient sex on the engraftment of the human leukemic and healthy cells. Donor human cells and recipient immunodeficient mice demonstrate sex-specific engraftment levels with significant differences observed in the lineage output of normal CD34⁺ hematopoietic stem and progenitor cells upon xenotransplantation. Intriguingly, human female donor cells display heightened sensitivity to the recipient mice's gender, influencing their proliferation and resulting in significantly increased engraftment in female recipient mice. Our study underscores the intricate interplay taking place between donor and recipient characteristics, shedding light on important considerations for future studies, particularly in the context of pre-clinical research.