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 deletion 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' congenic genetically marked normal ( + / + ) marrow cells into adult homozygous and control heterozygous mice. Pretreatment 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-