[Study of colony forming cells and aggregates (CFCA) in vitro in blood and bone marrow of patients with chronic myeloid leukemia: simplified bovine serum albumin gradient centrifugation].

In untreated CML patients (at diagnosis or in relapse) we find about the same number of CFC per 1.10(6) nucleated cells in the blood and bone marrow (sometimes, slightly greater in the blood than in the marrow). Application of density-cut separation shows normal number of CFC in the low density fraction (Ldf-CFC) of bone marrow cells from patients in remission. In 7 untreated patients (at diagnosis or in relapse), we have always found a greater number of Ldf-CFC in the blood than in the marrow, when the study is performed on the same day and in the same technical conditions. This difference is observed even if the leukocytes count is elevated and thence, the contamination of bone marrow cells by blood cells is presumably important. The percentage of peripheral blood Ldf-CFC seems to be positively correlated with the number of peripheral blood leukocytes. The highest percentage of Ldf-CFC (greater than 60%) have been found in 5 patients in relapse. Two of these have entered into the blastic phase of CML and the three others relapse repeatedly in the chronic form of the disease.