The ability of macrophages from head and neck cancer patients to kill tumor cells. Effect of prostaglandin inhibitors on cytotoxicity.

Monocyte-derived macrophages were isolated from the peripheral blood of 39 patients with either squamous cell carcinomas of the head and neck or basal and/or squamous cell carcinomas of the facial areas. Macrophages from 6 of the 27 patients with squamous cell carcinomas of the head and neck were cytotoxic toward the human tumor cells. When indomethacin, a prostaglandin inhibitor, was added to the noncytotoxic macrophages during the cytotoxicity assay, macrophages from 8 of the 27 patients became cytotoxic for the tumor cells. When 12 patients with basal and/or squamous cell carcinomas of the facial areas were studied, the macrophages from 2 of these patients possessed cytotoxic macrophages. In addition, when indomethacin was added to the noncytotoxic macrophages during the assay, the macrophages from two of these patients became cytotoxic. However, it was also noted that 19 of the 39 patients with either squamous cell carcinomas of the head and neck or basal and/or squamous cell carcinomas of the face possessed macrophages that were noncytotoxic toward the tumor cells in the presence and absence of indomethacin. Macrophage-mediated cytotoxicity was also found to be inhibited by factors present in many cancer patients' plasma. Twelve of the 30 patients with squamous cell carcinomas of the head and neck possessed a plasma inhibitory factor capable of suppressing macrophage-mediated cytotoxicity by more than 50%, whereas no plasma inhibitory factor was found in the patients with basal and/or squamous cell carcinomas of the face. In addition, 29 of the 30 patients studied were incapable of killing the tumor cells in vitro either because they possessed nonresponsive macrophages and/or they possessed a plasma inhibitory factor.