Abstract
The in vitro colony formation by marrow from 16 children with normal bone marrow and 27 children with acute leukemia (16 cases at onset or relapse, and 11 cases during complete remossion) has been studied. The number of colonies per 2×105 cells in normal bone marrow ranged between 126 to 504, and the average count was 259 colonies. This was a higher number of colonies than that in adult bone marrow. After 7 days of culture, colonies were macroscopically recognized as white spots. The ratio between compact colonies to loose colonies was approximately 2:1, when classified using an inverted microscope.
In 12 cases which had counts in excess of 95% of blasts at onset or relapse of acute leukemia, there was a decrease in colony formation. One case of ALL showed an almost normal colony forming capacity. All of the 4 cases with 30 to 60% of blasts developed colonies, but the number of colonies was less than that of normal bone marrow. Colony forming capacity in 11 cases with remission was similar to normal bone marrow. We consider that in some cases of acute leukemia at onset or relapse there may be blasts that can differentiate and maturate.
