CONTENTS OF TOTAL AND PROTEIN-BOUND CARBOHYDRATES ARE LOW IN LEUKEMICLEUKOCYTES FROM PATIENTS WITH ACUTE MYELOGENOUS LEUKEMIA

Leukemic leukocytes from 12 patients with acute myelogenous leukemia ( AML) and two patients with chronic myelogenous leukemia (CML) were iso lated by centrifugations in Percoll gradients, and examined for total carbohydrates. In leukemic leukocytes from 10 of these patients cerami de-bound carbohydrates were also determined. Protein-bound carbohydrat es were calculated by subtraction of ceramide-bound carbohydrates from total carbohydrates. In all samples analysed the contents of total an d protein-bound carbohydrates were much lower in leukemic leukocytes t han in normal neutrophils, irrespective whether the results were expre ssed relative to protein, DNA, cell number or dry mass. For immature l eukemic cells of M0-M1 phenotype differences up to 10-fold were observ ed. Contents of ceramide-bound carbohydrates, i.e. those of neutral an d acidic glycosphingolipids (GSLs) were also low in leukemic cells. Ho wever, when GSL carbohydrates were calculated as percentage of total c arbohydrates, GSLs in leukemic leukocytes were elevated in half of the AML patients but depressed in the other half. The results are discuss ed in the light of the hypothesis on GSL function by one of us (Koscie lak J., 1986, Glycoconjugate J. 3, 95-108). According to one element o f the hypothesis, during cell differentiation newly synthesized glycop roteins (GPs) that perform specific functions are added to house-keepi ng GPs that are present in plasma membranes of all types of cells. Thu s, during differentiation, the GP content of the cell membrane should increase and that of the so called ''membrane packing'' glycosphingoli pids should decrease.