Leukocyte lysozyme activity in myelocytic leukemia.

L YSOZYME, A CATIONIC POLYPEPTIDE of low molecular weight,’ is present in serum and in certain blood cells. The enzyme is found in granulocytes and monocytes but not in lymphocytes, red cells or platelets.23 Leukocyte lysozyme levels in general are increased in monocytic and decreased in lymphocytic leukemia.46 Varying levels have been reported in the myelocytic and monomyelocytic leukemias.4’T The variation in the reported values probably can be attributed in part to differences in the species and maturity of the leukocytes in the samples assayed. This report describes the results of lysozyme determinations on leukocytes and sera from patients with chronic myelocytic and acute myeloblastic leukemia.* Lysozyme activity was quantitated by biochemical technic and related to the leukocyte population sampled and the clinical status of the patient. The results show that such measurements provide a quantitative index of the extent of the malignant process in the circulating granulocytes and that serial assays of leukocyte lysozyme activity furnish a valuable prognostic tool in these disorders.