Therefore, this study aimed to compare the ability of four immunodeficient strains (NSG, NCG, NOG-EXL, and NSG-SGM3) to support and develop a human xenograft of CD34+ HSCs from fetal cord blood and describe the potential applications in human disease, including cancer, infectious disease, and graft-versus-host-disease (GvHD). This evidence concerns the gene CD34 and graft versus host disease.