Flow cytometry of TPA-induced changes in cells of chronic B-cell leukemias

Cells from 14 patients with chronic B cell leukemias were cultured for up to 7 days with TPA (160 nM) in order to induce maturation of the malignant cells. Five cellular parameters, which can be quantitated by flow cytometry were analyzed in such cultures. These parameters were cell size, cell cycle, RNA, neutral esterase activity and dye uptake in mitochondria. Cell size increased in 13/14 cases in TPA treated cells compared to control cells. Cell cycle analysis revealed a low percentage of cells in S and G2/M phase both in control and TPA-treated cultures of chronic B cell leukemias, while in cultures of peripheral blood mononuclear cells TPA caused a large increase of S and G2/M cells. Both in chronic B cell leukemias and in PBMC, TPA induced an increase of RNA staining and neutral esterase activity in all or most cultures. Furthermore the staining of mitochondria increased in most cases. In conclusion, multiple changes can be induced by TPA in chronic B cell leukemias without associated proliferation.