Effects of meclofenamate on natural killer cell activity

The effect of meclofenamate on natural killer cell activity was studied in a four hour 51Cr release assay. Meclofenamate, a nonsteroidal anti-inflammatory drug, had no effect on natural killer cell activity when added to the mixture of target (K562) and effector (peripheral blood mononuclear) cells either at the beginning of the reaction or when effector cells were pretreated with meclofenamate for 12-24 hours. However, a significant increase (p less than 0.0005) in the natural killer cell activity was seen when target cells were pretreated with meclofenamate for 12-24 hours prior to their mixing with effector cells. This increase in natural killer cell activity was observed consistently when target cells were taken from different donors.