Higher frequencies of apoptotic CD4 cells were found in unstimulated, PWM/SEB, or PHA stimulated culture from postchemotherapy patients (PC) than in normal control cultures. Cultures of PMN were cultured for 18 to 48 hours with medium alone or mitogens. Apoptosis was determined by flow cytometry using 7AAD uptake in CD4⁺ cells. Data include assays on patients ranging from 3 to 21 months postchemotherapy from the FLAC/paclitaxel study and the ACT study. Bar (▪) represents the mean and () SE of the assayed populations. Number of assays (n) and P value of the comparison between normal donors and postchemotherapy donors are indicated at the top.