A patient with relapsed refractory CLL who transformed to RS was treated with chimeric antigen receptor- (CAR-) modified T cells targeted for CD19 and later relapsed with a clonally related PBL [27], whereas most recently, Chan et al. reported on two cases with CLL who transformed to PBL following ibrutinib treatment [28]. The gene discussed is CD19; the disease is B-cell chronic lymphocytic leukemia.