Hypocholesterolemia as a manifestation of disease activity in chronic myelocytic leukemia

A patient with chronic myelocytic leukemia and hypocholesterolemia displayed marked fluctuations in plasma cholesterol in response to several therapeutic maneuvers. During chemotherapy there was a reciprocal relation between low density lipoprotein (LDL) cholesterol levels and the degree of leukocytosis and splenomegaly. LDL cholesterol increased after splenectomy, but continued to cycle inversely with the leukocyte count. Receptor-mediated degradation of 125I-labeled LDL (125I-LDL) by mononuclear cells in vitro also showed cyclical changes which were unrelated to the number of immature myeloid cells in the population or the level of plasma cholesterol. 125I-LDL degradation rate was normal or slightly increased during relapse and after remission was achieved, but was greatly increased when tested during periods of remission induction. This patient illustrates that significant changes in plasma total and LDL cholesterol occur in chronic myelocytic leukemia in association with alterations in proliferative state. Tumor load, the presence of an enlarged spleen, and changes in lipid metabolism of circulating cells all appear to contribute to the reduction in LDL cholesterol levels.