Elimination of adult T cell leukemia cells by ultrasound in the presence of porfimer sodium.

Sonodynamic effects using porfimer sodium (Photofrin; Pf) on leukemic and normal cells were evaluated. The purpose of this experiment was to compare cell survival among MT-2 cells, normal peripheral mononuclear cells (PMNCs) and adult T cell leukemia (ATL) patients' PMNCs after sonodynamic treatment. Cells were exposed to 450 kHz ultrasound at an intensity of 500 mW/cm2. The survival rate of MT-2 cells exposed to ultrasound alone for 80 s was 20.1 +/- 4.8%, whereas survival rates exposed to ultrasound in combination with 25, 50 and 100 microg/ml of Pf resulted in 11.5 +/- 2.9, 3.2 +/- 1.6 and 1.6 +/- 1.4%, respectively. There was a significant difference of cell survival between the group exposed to ultrasound alone and the Pf-combined groups (n = 6, p < 0.05). On the other hand, in the normal human PMNCs, no significant differences of cell survival rates were found between ultrasound-treated groups with and without Pf. We similarly examined the survival rate of PMNCs in the peripheral blood of five acute-type ATL patients (n = 5) after ultrasound (60 s, 300 mW/cm2) exposure with or without 100 microg/ml of Pf. Comparison of cell survival rate between ultrasound alone and ultrasound plus Pf showed significant differences (69.4 +/- 22.5 and 30.0 +/- 23.0%, respectively). There were no significant cytotoxicities in all Pf alone treated groups of the MT-2 cells, the normal PMNCs and the ATL patients' PMNCs (p < 0.05). It was suggested from this study that there was a specific selectivity of sonodynamic effects to MT-2 cell lines and ATL patients' PMNCs. It is anticipated that this new method of treatment, i.e. sonodynamic therapy, could be used for extracorporeal blood treatment of acute-type ATL patients.