Separation of chronic lymphocytic leukemia (CLL) cells by a discontinuous density gradient: Correlation with clinical stage

Peripheral blood or bone marrow cells of 15 patients with chronic lymphocytic leukemia (CLL) were separated on an albumin density gradient. In 5 of 5 CLL patients, the distribution of malignant B lymphocytes was similar across the gradient when blood and bone marrow were compared, but different from the distribution of cells from healthy volunteers. In 10 patients, B cell colony formation was measured in vitro from peripheral blood cells after gradient fractionation. Although most of the cells in all patients were found in fraction 4, the majority of B lymphocyte colonies were found in light density fractions (1+2, 3) in patients with more advanced disease (Rai stages 3 or 4), and in heavier fractions (4, bottom) in patients with less advanced disease (Rai stages 0, 1 or 2). The density of CLL cells might provide a new prognostic marker in this disease.