Indomethacin-mediated enhancement of lymphocyte response to mitogens in healthy subjects and lung cancer patients.

Indomethacin (prostaglandin synthetase inhibitor) was found to be capable of enhancing the mitogen-induced lymphocyte proliferative responses of healthy subjects and patients with lung cancer. A whole-blood culture technique was used. Indomethacin had no mitogenic activity. We observed a greater enhancement of lymphocyte response by indomethacin in weak responders as compared with strong responders in healthy subjects and lung cancer patients. A greater enhancement was also noted in lung cancer patients with active disease as compared with lung cancer patients in remission. In a separated cell culture system, the indomethacin exerted no effect on purified T cells in the absence of monocytes, while this agent exerted its enhancement effect on T lymphocyte response in the presence of autologous monocytes of lung cancer patients. This suggests that monocytes (suppressor cells) may secrete prostaglandins, which are responsible for the impairment of T lymphocyte response in lung cancer patients.