Effects of repeated doses of MDMA ("ecstasy") on cell-mediated immune response in humans

Cell-mediated immune response after the administration of two repeated dose s of 100 mg 3,4-methylenedioxymethamphetamine (MDMA) at 4-hour and 24-hour intervals was evaluated in two randomised, double-blind and cross-over clin ical trials conducted in healthy male MDMA consumers. MDMA produced a time- dependent decrease in the CD4/CD8 T-cell ratio due to a decrease in the num ber of CD4 T-helper cells, a decrease in the functional responsiveness of l ymphocytes to mitogenic stimulation, and a simultaneous increase in natural killer cells. In case of two 100 mg MDMA doses given 4 hour apart, immune alterations produced by the first dose were strengthened by the second one. At 24 hours after treatment, statistically significant residual effects we re observed for all the altered immune parameters after the administration of two MDMA doses if compared to single dose and placebo. In the second cli nical trial, the second 100 mg MDMA dose given 24 hours after the first dos e produced immunological changes significantly greater than those induced b y the initial drug administration and which seemed to show a delayed onset. Significant residual effects were observed for all the immune parameters a s late as 48 hours after the second dose. These results show that repeated administration of MDMA with both a short and a long time interval between d oses extends the critical period following MDMA administration, already obs erved after a single dose, in which immunocompetence is severely compromise d. (C) 2001 Elsevier Science Inc. All rights reserved.