Enhancement of T lymphocyte proliferative response to mitogens by indomethacin in breast and colorectal cancer patients.

The present study confirms previous observations that in vitro T lymphocyte proliferative response to mitogens is depressed in only some untreated patients with advanced or metastatic breast and colorectal cancer. Indomethacin, a prostaglandin synthetase inhibitor, at 1.0 microgram or 0.1 microgram/ml concentration significantly enhances the PHA, Con A or PWM response in these patients with breast and colorectal cancer (P less than 0.05 - P less than 0.01). Indomethacin has no mitogenic activity. Ethyl alcohol (0.01%), in which indomethacin is dissolved, also has no mitogenic or cytotoxic activity. Although the in vitro effect of indomethacin has been well-demonstrated, the in vivo effect of this agent on cell-mediated immunity in man has not yet been thoroughly investigated and thus, further studies of the effect of indomethacin administration on in vivo and in vitro cellular immunity seem warranted.