[Impulse cytophotometric studies of bone marrow and blood cells in children with acute lymphoblastic leukemia (ALL). 1. Bone marrow cells]

1. Compared with the peripheral blood lymphocytes of healthy children the cell fractions in the S- and G2 + M-phase are significantly higher in the bone-marrow of those children affected with ALL. This increase was proved in the SR- and MR-group irrespective of the cytomorphological subtype and cytochemical reaction. In patients with relapses the percentage of S-phase cells is below 6%. 2. In about 30% of our patients (mainly in the SR-group with L1-morphology) an initial DNA-aneuploidy was identified. As the risk of relapse is higher in children without DNA-aneuploidy, this symptom has a pretherapeutical-prognostic significance. 3. In the phase of hematological full remission, DNA-frequency distribution correlates with the proliferative activity of normal hematopoiesis. It provides no additional information about the pretherapeutical risk.