HbA and HbF and mRNA content among sorted erythroid human bone marrow populations.

(A) Bone marrow mononuclear cells were stained and sorted using the flow cytometric gates of CD71⁺ , GPA⁻ cells versus CD71⁺, GPA⁺ (rectangles). Stained cytospins of the postsort populations are shown on the right. (B) HPLC analyses of the control HPLC (top) showing the elution times of HbF and HbA versus sorted GPA⁺ cells (middle) and GPA⁻cells. Note differences in millivolt (mV) scales. (C) Quantitative PCR analyses of globin mRNA. Amplification curves of standard plasmid dilutions containing γ-globin (upper panel) and β-globin (lower panel) are shown in black. Amplification curves from total RNA extracted from the GA⁺CD71⁻ cells are shown in blue, while GA⁺CD71⁺-derived curves are shown in red. Increases in the amount of template mRNA molecules were detected by a decrease in the number of PCR cycles required to reach the emission intensity threshold level of 0.02 (bold horizontal line). ΔRn = fluorescence emission intensity.