CD19 and B-cell chronic lymphocytic leukemia: Accordingly, T cells from patients with large B cell lymphoma and chronic lymphocytic leukemia (CLL) who responded to CD19 CAR T cells were found enriched in gene expression profiles involved in early memory, or were rather the result of a single central memory T cell (TCM) clone derived from a TET2-targeted insertional mutagenesis event, as observed in a patient with CLL (4, 6, 23, 24).