Monocyte Functional and Metabolic Activity in Malignant and Inflammatory Diseases

Macrophages or monocytes produce CL upon exposure to ingestible particles such as opsonized zymosan or bacteria. In previous studies, we have demonstrated that activated macrophages from mice produce significantly more CL than do normal macrophages. In the present study, we have utilized the CL assay as well as 14C-1-glucose utilization to assess monocyte metabolic activity in a variety of malignant, infectious, and inflammatory diseases. Monocyte peak CL was significantly increased above control values (20.9 +/- 0.5 (S.E.) X 10(3) cpm) in 25 patients with lymphoma (26.7 +/- 1.5 x 10(3)). Markedly increased CL was also seen in inflammatory processes such as bacterial infections, tuberculosis, and sarcoidosis (32.2 +/- 2.7 x 10(3)). In contrast, monocytes from patients with solid tumors, including carcinomas of breast and gastrointestinal and genitourinary tracts, had peak CL values (22.4 +/- 1.6 x 10(3) which were not significantly different from controls. When studied by determining 14C-1-glucose utilization, hexose monophosphate shunt activity paralleled CL values. Monocyte metabolic activation appears therefore to accompany ongoing infectious or granulomatous processes and may also be present in certain malignancies associated with reticuloendothelial stimulation.