The Effect of Amelioration of Anemia on the Synthesis of Fetal Hemoglobin in Sickle Cell Anemia

Two adult patients with sickle cell anemia of blood group A and A₂B respectively, received sufficient transfusions of group O blood to maintain nearly normal hemoglobin concentrations for 4 months or longer.

Serial samples of the erythrocytes of each recipient were obtained by agglutination with anti-A (and anti-B) serum. The proportion of Hb F in the agglutinated erythrocytes was determined. Early in the transfusion period, a marked rise in the proportion of Hb F was noted. This rise was attributed to prolonged survival of erythrocytes which contained larger proportions of Hb F. In the later part of the transfusion period, the proportion of fetal hemoglobin declined to pre-transfusion levels or below. However, significant amounts of fetal hemoglobin in the erythrocytes of each patient were demonstrated throughout the period of study, and Fe⁵⁹ incorporation into Hb F in vivo was demonstrated in one patient after 4 months of transfusion therapy. Under the conditions of these studies, synthesis of Hb F continued despite prolonged correction of the anemia. A decline in the proportion of Hb F in the erythrocytes of one patient after 5 months of transfusions suggested that Hb F synthesis may ultimately be depressed by transfusions. It was suggested that the proportion of fetal hemoglobin observed in the erythrocytes might in certain diseases reflect the degree of anemia present many months before.