Comparison of 7-AAD and annexin V for the quantitation of apoptotic cell death.

AML patient cells were incubated overnight in 1% serum without growth factors and without (A, B) or with (C, D) 1 μmol/L PSC-833, the pgp reversal agent. We added 12.5 μg/mL 7-AAD to tubes (A) and (C). Tubes (B) and (D) were rinsed and stained with annexinV FITC and propidium iodide. Flow cytometer dot-plots illustrate nonviable cells: high 7-AAD in FL3, with decreased forward scatter in plots (A) and (C), positive annexin V in FL1 on plots (B) and (D). Secondary necrosis is also seen in plots (B) and (D) on the FL2 axis (propidium iodide incorporation). The percentage of cells determined by each method to be undergoing or to have undergone apoptosis is indicated on the plots.