Molecular ratios of HbF/HbF+HbA in whole-culture lysates.

Cultures were lysed and the relative amounts of fetal hemoglobin measured by cation exchange HPLC. The ratios HbF/HbF+HbA are multiplied by 100 to give the percentage of HbF. The 2 values plotted at the 0.1% level are from samples in which the HbF peak was too small for quantitation. Each value pair (connected) represents a separate, independent experiment in which all cells were harvested at 1 time point between day 8 and day 19. Different culture times are distinguished by symbols: Diamonds: day 8; crosses: day 11; circles: day 13 (3 different experiments); triangles: day 16; squares: day 19. The effect of TGFβ is significant with P < .01.