title: Correlation between Intracellular and Extracellular Lysozyme in Acute (Myelo)Monocytic Leukemia.
abstract: The localization of myeloperoxidase (MPO) or lysozyme was studied in leukemic cells by electron microscopy in an attempt to investigate why the level of lysozyme activity increases in the serum of patients with acute (myelo)monocytic leukemia. The specimens were obtained from 3 patients with acute monocytic leukemia and 4 with acute myelomonocytic leukemia with extremely elevated serum lysozyme levels (more than 100 μg/ml, normal: ∼10µg/ml). The granules containing MPO or lysozyme, surrounded by microfilaments, were observed in the periphery of the cytoplasm. MPO positive granules were considered tot contain lysozyme. Some granules appeared to be degranulation from the cell-membrane of viable leukemic cells. This observation supports the concept that there is a mechanism by which lysozyme-positive granules degranulation from viable leukemic cells and as a result the level of lysozyme activity becomes elevated in the serum. It also appears that MPO is discharged into the serum at the same time as lysozyme: is released.
authors.affiliation: a The Third Department of Internal Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Saito
keywords: Acute monocytic leukemia (M5b); Acute myelomonocytic leukemia (M4); Immunogold staining; Lysozyme; Myeloperoxidase