Apoptosis assay. LCLs from subjects with L/L (filled symbols) and with S/S (open symbols) were cultured for 24 hours with different concentrations of H₂O₂. Apoptotic cells were detected by the TUNEL method using a flow cytometer. Results are reported as means ± SDs among 5 lymphoblastoid cell clones from each subject. *Significantly greater than baseline (0 μM H₂O₂), P < .05.