Mononuclear phagocyte function in head and neck cancer: NBT-dye reduction, maturation and migration of peripheral blood monocytes.

The number of blood monocytes, their ability to mature into macrophages, their NBT-dye reduction capacity and their migration towards casein were studied in 29 patients with squamous cell carcinoma of the larynx, 12 patients with squamous cell carcinoma at other sites within the head and neck and two groups of male controls, one of 29.7 yrs. +/- 7.2 (SD) and the other of 71.4 yrs +/- 6.8 (SD). An age dependency of monocyte function in healthy individuals was established. Increased numbers of monocytes per ml blood were found in the older men. These cells showed an enhanced migration toward casein. Their maturation capacity was decreased. A clear impairment of migration toward casein was found in the two groups of carcinoma patients. The number of monocytes was only marginally affected. The maturation was found to be enhanced. An impaired recruitment of mononuclear phagocytes at the site of malignant growth due to diminished migratory capacities might be important for failing immune surveillance.