Inhibition of tumor necrosis factor-stimulated human peripheral blood polymorphonuclear cell iodination by sera from various cancer patients

: Tumor necrosis factor (TNF) dose- and time-dependently stimulated the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN). The addition of sera obtained from patients with brain tumors, or gastric, pancreatic, hepatocellular, common bile duct or lung carcinoma significantly inhibited TNF-stimulated PMN iodination, whereas sera of normal volunteers were, in general, not inhibitory. TNF-stimulated iodination of human peripheral blood monocytes was almost eliminated by brain tumor patient sera, but was significantly enhanced by normal human sera. Specific [135I] TNF binding to the PMN receptors was significantly increased in the presence of either patient sera or normal sera. These data suggest some mechanism other than modification of TNF receptor binding for expression of the inhibitory action of cancer patient serum.