Time- and dose-dependence of TC-A—induced apoptosis. Peripheral blood mononuclear cells (PBMCs) of 4 patients were left untreated or treated with TC-A at the indicated concentrations for 4 hours, 8 hours, 16 hours, or 24 hours. Subsequently, (A) changes in cell volume and granularity reflecting a decrease in viability and (B) the increase in annexin V—FITC binding was determined by flow cytometry in B-CLL cells. (C) In parallel, apoptosis of CD4⁺CD8⁺ T cells using the annexin V—FITC binding assay was determined. The mean values representing the differences between TC-A—induced apoptosis minus spontaneous apoptosis ± SEM of 4 independent experiments are shown.