Depressed natural killer cell activity in cervical lymph nodes containing focal metastatic squamous cell carcinoma

Natural killer (NK) cells are a subpopulation of lymphocytes involved in host defense against tumor cells. Although a great deal of clinical research has focused on the role of NK cells in the blood of patients with cancer, very little has been done to determine what role they may play at the regional or lymph node level. One hundred seven lymph nodes from 22 patients with head and neck cancer and eight control patients were assayed for NK cell cytotoxicity against the human erythroleukemia cell line K562. Six of these nodes contained a discrete intracapsular focus of metastatic tumor. Lymphocytes from these focally positive nodes exhibited a significant depression of NK cell cytotoxicity compared with all other nodes. These data suggest that the presence of metastatic tumor inhibits NK cell function at the regional level in patients with head and neck squamous cell carcinoma.