Lysozyme Activity in Hematologic and Non-hematologic Disorders with Special Reference to Reactive Monocytosis Associated with Chronic Infections and Inflammatory Reactions

Abstract

The clinical significance of serum and urinary lysozyme estimation was evaluated in patients with hematologic and non-hematologic disorders. Markedly increased serum lysozyme ranging from 17.0 to 150.0 μ/ml with the mean of 48.1 μ/ml and profuse lysozymuria with the mean daily excretion of 938 mg were observed in monocytic leukemia. Slight to moderate increases of serum lysozyme were found in chronic myelocytic leukemia with the mean of 16.7 μ/ml and polycythemia vera with the mean of 15.1 μ/ml, and in the former disease lysozymuria was less marked, except for one excreting 110 mg per day, than that in monocytic leukemia. In cases of acute and chronic lymphocytic leukemias, lysozyme levels lower than normal serum levels were detected. With regard to lysozyme activity in reactive monocytosis, a case of miliary tuberculosis with pulmonary and hepatosplenic involvement was presented in which moderately elevated serum lysozyme and a large amount of lysozyme in urine to such an extent as suggestive of monocytic leukemia were found by serial estimations. Two other patients with miliary tuberculosis, who were undergoing chemotherapy, showed increased serum lysozyme activities. An additional case with possible diagnosis of cholecystitis exhibited peripheral monocytosis and greatly increased serum and urinary lysozyme concentrations. Such cases suggest that proliferation of monocytic cells, not only in leukemia but also in the rare conditions including prominent reactive monocytosis (3-5×10¹¹ monocytes in the body), can cause marked increase of lysozyme when the amounts of lysozyme exceed the capacity to dispose the enzyme by catabolic mechanism. Pulmonary tuberculosis with varied degrees of disease activity did not cause an increase of lysozyme, while in patients with sarcoidosis elevated serum lysozyme activities were observed, indicating that total mass of monocytic cells were increased in the latter conditions. On the other hand, proliferation of lymphoid cells and reticuloendothelial cells resulted in no increase of lysozyme. Non-hematologic disorders such as hepatic, cardiac disorders and neoplasm except for renal disease caused no increase of lysozyme.