Abstract

A hematological study on the 161 cases of aplastic anemia was done emphasizing the correlation between the bone marrow finding and the etiological background and hematological values. The cases involved in this study were selected from the accumulated cases during a period of 13 years from 1960 to 1973, in the Department of Clinical Pathology, College of Medicine, Seoul National University. The results are summerized as follows. 1. Age distribution of aplastic anemia was highest in 10 to 19 years of age group and male to female ratio was l.6 : 1. 2. Idiopathic type of unknown etiology was 75.2 percent of the total 161 cases and the most common etiological agents suggested in secondary type were benzene (5%), chloramphenicol (5%), herb medicines (5%), and the antibiotics other than chloramphenicol (3.7%) 3. Anemia was the most commonly encountered initial symptom with the hematocrit value of 0∼19 volume percent in 53% and hemoglobin value of 0∼5.9gm/dl in 50% of the total aplastic anemia patient respectively. The initial value of corrected reticulocyte count was less than 0.55 percent in 77 percent of total cases. 4. Initial WBC count was ]ess than 2,000/mm3 in 24% of total cases, however the lowest WBC count during hospital course was less than 2,000/mm3 in 45 percent of total cases. 5. Initial platelet count was less than 30,000/mm3 in 29 percent and only 19 percent of total cases showed more than 100,000/mm3. The lowest platelet count during hospital course was less than 30,000/mm3 in 45 percent and more than 100,000/mm3 in 10 percent of the total cases respectively. 6. The cellularity of bone marrow was normocellular to hypercellular in 14 percent and the remaining cases were hypocellular to acellular. Total nucleated cells and immature granulocytes are decreased in reverse proportion to the increase of lymphocytes. There was no definite relationship between the number of normoblast and the cellularity of bone marrow, but the number of lymphocytes and plasma cells were significantly increased in hypocellular marrow. 7. Tissue basophils and reticulum cells were more frequently encountered in hypersensitivity type and especially in hypocellular type of marrow. 8. Some cases of aplastic anemia due to herb medicine showed an increased number of tissue basophils and reticulum cells in bone marrow. In summary, the bone marrow findings of the aplastic anemia, especially those of hypersensitivity type showed an increased number of lymphocytes, plasma cells, tissue basophils and reticulum cells strongly suggesting the immunologic reactions in the initiation of aplastic anemia.