Inhibitory effect of hepatocellular carcinoma [HCC] sera on natural killer [NK] cell activity

ABSTRACT

The role of inhibitory factors [IFs] in the sera of cancer patients as a responsible factor for natural killer [NK] suppression was demonstrated in some types of cancer. In this study, we tried to investigate the presence of IF [s] in the sera of HCC patients. NK. cells were isolated from normal healthy donors and these cells were incubated with sera from 37 BCC patients at different stages of the disease as well as with sera from normal healthy controls of matched age and sex. After 4hr incubation, NK. activity was measured by standard Cr51 release assay. The levels of IgG, IgM and IgA immune complexes in sera of patients and controls were measured by ELISA technique. Results showed significant suppression of. NK. cell activity after incubation with BCC sera compared to control sera. The degree of depression of NK. activity was concentration dependent; there was slight suppression at 5% serum concentration and it was maximized at 25-50%. Levels of immune complexes were significantly higher in patients than controls except IgM-IC. We conclude that there is some IF [s] in the sera of HCC patients which may contribute to depression of NK activity in these patients. One of these factors might be tumor antigen-antibody complexes