Hematopoietic Repopulation of Adult Mice With P-Thalassemia

Deletion of the murine &major globin gene on chromosome 7 causes a severe, hypochromic anemia in homozygous mice. We show that over 50 % of the homozygous mice die either in utero or at birth. Mice heterozygous for the dele-tion have a slightly increased percentage of reticulocytes when compared with normal mice, but no clinical anemia. As a therapeutic measure, we transplanted 2 X 10 ' con-genic genetically marked normal ( + / +) marrow cells into adult homozygous and control heterozygous mice. Pre-treatment with marrow ablative irradiation was required to obtain significant percentages of donor peripheral blood cells in the homozygous mice. Red blood cell (RBC) counts normalized after pretransplantation irradiation of thalasse-ICE HOMOZYGOUS for the deletion of one of the two adult @-globin genes develop a condition resem-blin