Monocytic production and plasma bioactivities of interleukin-1 and tumour necrosis factor in human cancer.

Plasma concentrations and in-vitro production of interleukin-1 and tumour necrosis factor were evaluated in 23 weight-losing patients with cancer, six bacterially infected patients without cancer and six healthy controls. Bioactivity of interleukin-1 was found in the plasma from five of six bacterially infected patients but only from one of 23 cancer patients. Tumour necrosis factor activity was not detected in the plasma of any patient. In four of 23 patients with cancer, in-vitro stimulation of peripheral blood monocytes by either endotoxin or heat-killed Staphylococcus albus resulted in no significant production of interleukin-1. Such a defect was not seen in any of the bacterially infected or control patients. Tumour necrosis factor production by endotoxin-stimulated blood monocytes was unaffected by the presence of cancer or bacterial infections and was normal in the four individuals with defective interleukin-1 production. We can therefore conclude that interleukin-1 bioactivity is not generally found in the plasma of weight-losing cancer patients. Furthermore, in a fraction of such cancer patients, monocytic production of interleukin-1 is markedly down-regulated. However, this defect appears to be specific for interleukin-1 since in-vitro tumour necrosis factor production is normal.