Studies on the anti-inflammatory properties of thalidomide: effects on polymorphonuclear leukocytes and monocytes.

The effects of thalidomide on polymorphonuclear leukocyte (PMN) and monocyte function were studied in vitro. Phagocytosis of latex beads by both PMNs and adherent monocytes was significantly depressed (p less than 0.01) after a 1-hour incubation of cells with 10 microgram/ml of thalidomide. Concentrations of 1 microgram/ml stimulated monocyte phagocytosis (p less than 0.01) but did not influence PMNs. Incubation of monocytes with 10 micrograms/ml resulted in a significant reduction of chemiluminescence (CL) but had no effect at 1 microgram/ml concentrations. There was no significant action on PMN CL at either concentration. Finally, 10 micrograms/ml concentrations of thalidomide were not cytotoxic for either cell type after 18-hour incubations. In conclusion, the results of these studies may at least partially explain the efficacy of thalidomide in some inflammatory conditions.