Ortho-hIL-2Rβ+ CAR-T cells were administered to xenograft CD19+ Nalm6 leukemia murine models, followed by administration of ortho-hIL-2 daily or every other day for 2 weeks.65 Higher doses of ortho-hIL-2 led to weight loss and higher mortality rates, and experiments with NSG mice indicated that lower doses led to more effective leukemia control with fewer instances of mouse death. This evidence concerns the gene CD19 and leukemia.