Comparative effects of various antidepressant drugs and the immunosuppressant dexamethasone on the T-lymphocyte proliferative response in vitro

The objective of this study was to use the whole blood lymphocyte prolifera tion method to assess the immunotoxic potential of the antidepressants imip ramine (a tricyclic antidepressant, TCA), fluvoxamine (a selective serotoni n reuptake inhibitor, SSRI) and venlafaxine (a serotonin/noradrenline reupt ake inhibitor, SNRI). In addition, we used the known immunosuppressive comp ound dexamethasone to compare the magnitude of the inhibitory response (IC5 0 value) with that of the antidepressants. There was a 10-fold difference i n the concentrations of the antidepressants that inhibited concanavalin A-s timulated lymphocyte proliferation. However, the inhibitory concentration o f dexamethasone was almost 1,400 times lower than any of the antidepressant s. The difference in the magnitude of the inhibitory response between the a ntidepressants and dexamethasone suggests that the antidepressant effect ma y be of little clinical relevance. As the functional reserve of the immune system is poorly understood, however, it remains a possibility that some an tidepressants may accumulate in vivo in a sufficiently high concentration t o inhibit lymphocyte proliferation. Med Sci Res 27:773-774 (C) 1999 Lippinc ott Williams & Wilkins.