A pool of free α-globin chains was found in the bone marrow samples from three controls, two patients with β-thalassemia trait, three with sickle β-thalassemia, three with hemoglobin (Hb) Lepore trait, one with αβ-thalassemia, four with homozygous β-thalassemia, and one doubly heterozygous for Hb Lepore and β-thalassemia. The average percentage of newly synthesized α-chains found in the free α-globin pool was 6.2% in the controls and 33.0% in the patients heterozygous for thalassemia or Hb Lepore. These controls and patients had balanced β- and α-globin synthesis in the bone marrow. In the homozygous patients and in the one patient doubly heterozygous for thalassemia and Hb Lepore, there was a marked deficit of β-chain synthesis in the bone marrow and also a large pool of newly synthesized free α-chains. The function of this pool of free α-chains is not known, but it may be involved in the regulation of globin chain synthesis in normal patients and in the compensatory synthesis of β-chains that occurs in the bone marrow of patients heterozygous for thalassemia or for Hb Lepore.
Frances M. Gill, Elias Schwartz