In vitro effect of indomethacin on mitogen-induced lymphoproliferative response in lung cancer patients.

There is some evidence that prostaglandin (PGE)-secreting cells may have a role in immunosuppression in cancer patients. In this work we investigated the effects of indomethacin--a PGE synthesis inhibitor, on PHA-induced lymphoproliferative response in vitro. Twenty patients with lung cancer before therapy were included in this study. When compared to controls, the patients had significant decrease of T cell number and proliferative response to PHA (p less than 0.001) and increased number of mononuclear phagocyting cells (p less than 0.001). The degree of depression of lymphocyte response did not correlate with the number of mononuclear phagocytes. The presence of indomethacin in the culture induced significant (p less than 0.01) improvement of the reactivity in high percentage (75%) of patients with diminished lymphoproliferative response to PHA. In the patients with normal lymphocyte response, indomethacin did not change reactivity to PHA. These results indicate that PGE-secreting cells may contribute to the immune depression in lung cancer patients, and that indomethacin may have therapeutical potential in some patients.