Comparative study of the endotoxin-stimulated nitroblue tetrazolium test in disease and health

Endotoxin-stimulated nitroblue tetrazolium (NBT) reduction was evaluated in 853 individuals: 270 healthy controls, 334 with various non-neoplastic conditions, 220 with solid non-lymphomatous tumours, and 29 with lymphoma. Each of the above groups was divided into three age subgroups: less than 60, 60-69, and greater than or equal to 70 years. In the controls and in patients with nonmalignant diseases, significantly lower values were recorded for elderly subjects (greater than or equal to 60 years) compared with younger subjects of the same group, whereas in cancer patients the results were independent of age. Under the age of 60, stimulated values for both patient groups were significantly lower than the control values, and in patients with solid non-lymphomatous tumours significantly lower values were attained than in the other patients. NBT reduction in lymphoma patients was comparable to that of the controls. In the elderly (age greater than or equal to 70) no significant differences were noted between patients and controls. It is suggested that stimulated NBT reduction declines with advancing age. While this test clearly demonstrates some leucocyte dysfunction in solid cancer, its value in investigating neutrophil behaviour in elderly subjects is questioned.