Free alpha-globin pool in human bone marrow.

A pool of free alpha-globin chains was found in the bone marrow samples from three controls, two patients with beta-thalassemia trait, three with sickle beta-thalassemia, three with hemoglobin (Hb) Lepore trait, one with alphabeta-thalassemia, four with homozygous beta-thalassemia, and one doubly heterozygous for Hb Lepore and beta-thalassemia. The average percentage of newly synthesized alpha-chains found in the free alpha-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 beta- and alpha-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 beta-chain synthesis in the bone marrow and also a large pool of newly synthesized free alpha-chains. The function of this pool of free alpha-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 beta-chains that occurs in the bone marrow of patients heterozygous for thalassemia or for Hb Lepore.