Notably, in the peripheral blood the effect of PAPTP was highly significant as it caused an almost six-fold decrease of CLL B cells (Fig. 3a) (n = 7, pre-therapy: 9562 ± 3494 CD5+CD19+ /mm3 blood; PAPTP: 1665 ± 345 CD5+CD19+ /mm3). This evidence concerns the gene CD19 and B-cell chronic lymphocytic leukemia.