STUDIES ON THE PROLIFERATIVE ACTIVITY OF ERYTHROBLASTS IN VARIOUS TYPES OF ANEMIA USING MITOTIC INDEX AND LABELING INDEX OF 3H-TdR

Abstract

Mitotic index (MI) and 3H-TdR labeling index (LI) were determined in hematologically normal subjects and patients with various types of anemia. The results obtained were as follows : 1) In patients with hemolytic anemia, iron deficiency anemia, or acquired sideroblastic anemia, there was no significant difference in both MI and LI of basophilic, polychromatic or total erythroblasts as compared with those in normal subjects. No significant difference was also observed in these values in patients with aplastic anemia or pernicious anemia except for significant decrease in LI or MI of total erythroblasts, respectively.2) The lower value of LI or MI of total erythroblasts in aplastic anemia or pernicious anemia, respectively, was presumed to have been caused by the increase in number of orthochromatic erythroblasts.3) In patients with pernicious anemia, treatment with parenteral Vit. B12 resulted in a significant increase in both MI and LI of polychromatic erythroblasts to normal levels.4) In cases of erythroleukemia, both LI and MI of basophilic or polychromatic erythroblasts were significantly lower as compared with those in normal subjects. From these results it is suggested that proliferation activity of erythroblasts is obviously reduced even in an earlier stage of the maturation.5) Mitotic duration of the bone marrow erythroblasts was determined using stathmokinetic method in one case of pernicious anemia and 2 cases of hemolytic anemia. Among these patients, no significant difference was observed in mitotic duration and mean value was 43.6 ± 3.1 minutes. From this value the generation time of total erythroblasts was calculated as 26.3 ± 2.3 hours.6) In all patients with above mentioned anemias and normal subjects there was significant correlation between MI and LI of total or polychromatic erythroblasts. Significant correlation was also observed between these values, both in patients with increased ineffective erythropoiesis such as pernicious anemia, erythroleukemia, acquired sideroblastic anemia and in those without increased ineffective erythropoiesis such as iron deficiency anemia, hemolytic anemia and aplastic anemia. There was no significant correlation between MI and LI in basophilic erythroblasts. The main reason is surmised to be low cell counts. Therefore using MI, it seems to be possible to presume the proliferative activity of erythroblasts similarly to using LI. MI seems to be less accurate than LI but easy to obtain from observation of usual bone marrow smears. In the case of MI, neither3H-labeled thymidine nor specialized technique of radioautography is required.7) There was no significant correlation between PIT in ferrokinetics and LI or MI in these patients, but in patients with high MI and LI, the RCIT tended to be high. In cases without increased ineffective erythropoiesis, MI was found to have significant correlation with both PIT and RCIT. Further investigation was required in order to be able to evaluate these results and draw a definite conclusion as to the correlation of MI and LI to ferrokinetics.From the results above described, the changes in proliferative activity of erythropoiesis in patients with various types of anemia were discussed.