[The interrelation of serum lysozyme level and cytoplasmic lysozyme level]

Abstract

By means of the immunocytochemical method, the level of cytoplasmic lysozyme in leukocytes from healthy volunteers (n = 50) and from patients with uremia (n = 50), leukocytosis (n = 50), various forms of leukemia (n = 36) and myelodysplastic syndrome (MDS) (n = 7) were analysed, and compared with that of simultaneously assayed serum lysozyme. Both the cytoplasmic and serum levels of lysozyme in uremia and leukocytosis were significantly higher than normal subjects (p < 0.001). No correlation, however, was found between their cytoplasmic and serum levels of lysozyme. Morphological analysis for various kinds of leukemia and MDS indicated that myelocytic and monocytic cells became highly positive for lysozyme staining with maturation, and that lymphocytes, leukemic myeloblasts and monoblasts were negative. The cytoplasmic and serum lysozyme levels of leukemias or MDS having a number of lysozyme-positive cells were elevated as compared with those of normal individuals. Among them acute myelocytic leukemia (FAB M4) revealed an excellent correlation between the lysozyme levels in cytoplasm and in serum. The rest whose serum lysozyme level tend to be lower than the cytoplasmic one gave poor correlation. Thus, serum lysozyme level is not fully reflected by the cytoplasmic level. The dual determination of cytoplasmic and serum lysozyme is suggested to be helpful on estimating leukemia types, the degree of cellular maturation and total cell mass, and might also provide a valuable tool for prediction of prognosis for these disorders.