CD4 and acute lymphoblastic leukemia: Interestingly, the 89Zr-mCD4-Mb uptake in hCD4+ HPB-ALL tumors, which served as another control group, was slightly higher than the 89Zr-hCD4-Mb uptake in CD4- DHL tumors (Figure 2A, 2C - D; Figure S2C), indicating mCD4+ cell infiltration in T-cell-deficient NSG mice.