To better profile the CRS potential of different cell products, we took advantage of the humanized mouse model developed in our unit.28 Briefly, SGM3 mice were reconstituted with human HSPCs, infused with the B-ALL cell line NALM-6 and treated with anti-CD19 CD4 or CD8 CAR-T cells carrying either CD28 or 4-1BB (figure 3A). Here, CD4 is linked to acute lymphoblastic leukemia.