抄録
Hematologic and cytogenetic studies were made on five cases of leukemia patients who had history of atomic bomb exposure and blood disorders such as anemia and/ or leukopenia for 5 or 13 years preceding the terminal development of acute leukemia (The first group). Of the 5 cases, 3 were exposed within 1,000 meters from the hypocentre. The type of leukemia in these patients were 3 of erythroleukemia, 2 of acute monocytic leukemia. Hematologically abnormal characteristics in the preleukemic stage in these cases were anemia (all cases, 5/5), monocytosis (4/5), prolonged leukopenia for over 10 years (4/5), appearance of erythroblasts in the blood one to 5 years prior to the development of leukemia (4/5), erythroid hyperplasia in bone marrow (3/5), maturation arrest in the granulocyte series (3/5) and presence of abnormal mitosis resulting in bi-nucleated immature granulocytes in bone marrow and its maturation forms in blood (3/5). Chromosome aberrations were observed in 4 of the 5 cases in the period before their leukemia became overt clinically.
There were other 5 cases with anemia (sideroblastic, PNH and aplastic) which had chromosome aberrations in the bone marrow cells but were not being diagnosed as leukemia yet (The second group). Cytological studies revealed the same kind of abnormalities including bi-nucleated immature granulocyte in the patient with sideroblastic anemia but not in PNH and aplastic anemia.
Furthermore, five heavilly irradiated persons were presented who had abnormal chromosomes with some clones in their marrow cells without any clinical complaints and signs (The third group).
Morphologically abnormal characteristics, especially presence of bi-nucleated immature granulocyte, and bone marrow chromosome aberrations in the preleukemic stage was discussed in terms of leukemogenesis following radiation exposure.
