BFU-E colony growth and fetal hemoglobin production in thepresence of zileuton for sickle cell and healthy individuals in methylcelluloseculture. Peripheral blood mononuclear cells were cultured as described in “Patients, materials, and methods.” The results are expressed as the number of BFU-E colonies per 3 × 105 mononuclear cells (MNCs). □ indicates sickle cell samples; and ▦, normal samples. Panel A demonstrates the BFU-E colonies on day 14 in the presence of zileuton at 0 to 100 μM concentrations. Panel B represents Hb F for sickle cell (□) and normal samples (▦). Note Hb F induction for both groups tested. Error bars represent SEM (n = 4 for each concentration/groups reported); each study done in triplicate.