OBJECTIVEFunctional defects in NK cells have been proposed to be responsible for the impairment of anti-tumor immune responses. However, it remained unclear whether the function of NK cells were impaired in patients with hepatocellular carcinoma. To address this issue, we analyzed the frequency and function of peripheral NK cell subsets in hepatocellular carcinoma (HCC) patients.

METHODS35 HCC patients and 24 healthy controls (HC) were enrolled in the study. Peripheral NK frequency was analyzed using flow cytometry. In addition, the capacity of NK cells to produce IFN gamma and to lyse K562 cells was evaluated.

RESULTSIn contrast with the healthy controls, the frequency of peripheral NK cells in hepatocellular carcinoma patients was decreased (12.19%+/-10.85% vs 24.01%+/-8.78%, u = 4.01, probability value less than 0.01), while the frequency of CD56(bright)CD16(neg) NK cells was increased (0.62%+/-0.39% vs 0.48%+/-0.28%, u = 1.96, probability value less than 0.05), and the frequency of CD56(dim)CD16(pos) NK cells was significantly decreased (11.59%+/-7.49% vs 22.66%+/-8.84%, u = 3.92, probability value less than 0.01). In addition, peripheral NK cells from HCC patients exhibited decreased capacity to produce IFN gamma (effective cells 13.31%) and to lyse K562 cells (mixed ratio 30:1, 10:1, 1:1, effective cells 16.72%+/-7.33% vs 26.29%+/-12.36%, u = 2.52, P less than 0.05, 8.01%+/-4.40% vs 13.09%+/-5.03%, u = 3.32, probability value less than 0.05, 3.51%+/-2.82% vs 3.42%+/-1.64%, u = 1.56, probability value more than 0.05, respectively) as compared with healthy subjects.

CONCLUSIONAnti-tumor activity of NK cells in HCC patients was impaired.