FLT3 and congenital rubella syndrome: Since CRS needs to be investigated before clinical trials using new immunotherapies, CRS has been modelized in HIS mice, but human cytokines were not observed in NSG mice humanized with hCD34+ cells and injected with OKT3 (Matas-Céspedes et al., 2020), unless using also fetal liver and thymus (Yan et al., 2019) or using immunodeficient mice with human hSIRPα and also deficient in Flk2 (BRGSF) (Martin et al., 2024).