The effect of colorectal malignancies on monocyte migration, lysozyme production, and phagocytosis

Peripheral monocyte migration, phagocytosis and lysozyme production has been investigated in 46 patients with colorectal malignancies. The diagnosis of colorectal carcinoma was based on clinical, radiological, and endoscopic examinations and confirmed histopathologically after removal of the tumour. The results were compared with a group of 36 normal healthy controls. Monocytes from patients with colorectal malignancies displayed reduced migration towards the chemotactic agent (P less than 0.001), random migration (P less than 0.001), and phagocytic activity (P less than 0.01) compared to normal controls. Lysozyme production by monocytes from patients with colorectal malignancies was significantly increased (P less than 0.01) compared to control subjects. The impairment in monocyte function in patients with colorectal carcinoma was not due to direct serum factors or to abnormal blood biochemistry, suggesting that the defect is intrinsic to the monocytes. These results suggest that an impairment in monocyte function may play an important role in the control of malignancies by cellular immune processes.