In vitro exposure of NK-92 cells to serum from patients with non-small cell lung cancer impairs their cytotoxicity.

Aim: To investigate the effect of serum from patients with non-small cell lung cancer (NSCLC) on in vitro cytotoxicity of the clonal cell line NK-92.

Materials And Methods: Twenty-six patients with NSCLC were included in this study. NK-92 cells were incubated in medium supplemented with 25% of each patient's serum (before and after chemotherapy) for 24 h, then washed and tested for cytotoxicity against NK-sensitive K562 targets.

Results: The cytotoxicity of NK-92 cells exposed to serum from patients with NSCLC before chemotherapy initiation was significantly reduced compared to that upon incubated with serum from healthy individuals (p<0.001). NK-92 cytotoxicity was further reduced upon exposure to patient's serum after the first and third chemo therapy cycles (p<0.001).

Conclusion: The results of our in vitro study suggest that serum of patients with NSCLC may exert per se an inhibitory effect on the cytotoxicity of NK-92 cells and this negative regulation may be enhanced with chemotherapy.