Fetal hemoglobin-containing cells have the same mean corpuscular hemoglobin as cells without fetal hemoglobin: A reciprocal relationship between gamma- and beta-globin gene expression in normal subjects and in those with high fetal hemoglobin production

We have developed methodology that allows comparison of the mean corpuscular hemoglobin (MCH) of fetal hemoglobin (HbF)-containing red cells (F cells) with the MCH of non-F cells from the same individual. To do this, suspensions of peripheral blood erythrocytes and their internal contents are fixed with an imidodiester, dimethyl-3,3'-dithiobispropionimidate dihydrochloride (DTBP). Thereafter fixed cells are made permeable to antisera by treatment with Triton X-100 and isopropanol, reacted with a mouse monoclonal antibody (MoAb) against HbF, and then with fluorescein-conjugated antimouse IgG. No appreciable hemoglobin is lost during such manipulation. Red cells from a diversity of subjects were thus treated and examined microscopically, first by transmitted light and then by epifluorescence. A direct correlation between Coulter-derived MCH and mean absorbance of 415 nm transmitted light was found for 100 unfixed (r = 0.96) and for 100 antibody-treated fixed-permeabilized red cells (r 0.99) among individuals selected so as to provide a range of Coulter MCH values between 20 and 35. Comparisons of microscopically derived MCH of F cells and non-F cells were statistically nondistinguishable (P > 0.05) in all subjects. Such comparisons included normal individuals (less than 1% F cells), SS patients (7% to 48% F cells), subjects with congenital anemia (22% to 65% F cells), individuals with heterocellular hereditary persistence of HbF (HPFH) (12% to 21% F cells), and heterozygotes for beta⁺ thalassemia (11% to 31% F cells). We conclude that gamma- and beta-globin production within F cells is regulated in a reciprocal fashion both among normal individuals and among individuals with elevated HbF production.