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 lymp hocytic leukemia (CLL) were separated on an albumin density gradient. In 5 of 5 CLL patients, the distribution of malignant B lymphocytes wa s 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 p eripheral blood cells after gradient fractionation. Although most of t he cells in all patients were found in fraction 4, the majority of B-l ymphocyte colonies were found in light density fractions (1+2, 3) in p atients with more advanced disease (Rai stages 3 or 4), and in heavier fractions (4, bottom) in patients with less advanced disease (Rai sta ges 0, 1 or 2). The density of CLL cells might provide a new prognosti c marker in this disease.