NK cell dysfunction with down‐regulated CD16 and up‐regulated CD56 molecules in patients with esophageal squamous cell carcinoma

NK cells can be divided into two subsets, CD56^dim and CD56^bright NK cells, based on their expression of CD56 and CD16. In the present study, we analyzed NK cell dysfunction in patients with esophageal squamous cell carcinoma (ESCC), with a particular focus on the expression of CD16 and CD56 molecules. Expression of CD16 and CD56, and the distribution of CD56^dim or CD56^bright NK cells gated on CD56(+)CD3(–) NK cells were compared between ESCC patients (n= 40) and healthy donors (n= 38). Purified NK cells were evaluated for Cetuximab‐mediated antibody‐dependent cellular cytotoxicity (ADCC) against epidermal growth factor receptor (EGFR)‐expressing ESCC cell lines. Although there were no significant differences in the distribution of CD56^dim and CD56^bright NK cells between ESCC patients and healthy donors, down‐regulated CD16 and up‐regulated CD56 were significantly observed on NK cells of ESCC patients, paralleling the impairment of Cetuximab‐mediated ADCC, in comparison with healthy donors. After patients received curative resections of ESCC, the down‐regulated CD16 and up‐regulated CD56 were significantly restored to the levels of healthy donors. Moreover, TGF‐beta1 partially contributed to down‐regulation of CD16 on NK cells. Down‐regulated CD16 and up‐regulated CD56 molecules on NK cells were observed in ESCC patients, resulting in NK cell dysfunction.