Purpose: Immunological, neuroendocrine: To investigate changes in cell-mediated immune function after the administration of 2 doses of MDMA, separated by 4 or 24 hours, in a attempt to imitate conditions experienced by some ecstasy users

Design: Study 2: Randomized placebo-controlled between-subjects / within-subjects design; ambiguous text concerning exact nature of design. Drug 1 (placebo or 100 mg MDMA) served as one apparently within-subjects factor, and Drug 2 (100 mg MDMA or placebo administered 24 h later) served either as a between-subjects or a within-subjects factor. All participants were enrolled in 2 sessions, with comparisons made after the second dose of MDMA. Immunological function, plasma cortisol and plasma MDMA was measured in all participants. Subjects: 9 MDMA-experienced males. Age and recruitment method not reported. May have been recruited through "word of mouth" as were participants in Mas et al, 1999.

Criteria for Inclusion - No information provided concerning inclusion or exclusion criteria. However, past papers published by this team have included individuals who were healthy, as determined via physical and psychiatric examination, with no current drug or alcohol dependence save for nicotine. All participants had to be male and had to have used ecstasy on at least 5 occasions without adverse reactions to the drug. In previous reports, these researchers have also verified that participants in their MDMA studies have extensive cytochrome P450 isozyme 2D6 activity. Although it was not stated in this publication, the same criterion was probably used here.

Measures: Immunological Function - Complete blood profile and cell count conducted on blood drawn from each subject, with samples drawn 1.5, 4, 6, 25.5, 28, 30, 48, 54 and 72 h post-drug 1. Authors did not test lymphocyte response to mitogens (phytohemagglutinin) in Study 2. Dual-color immunophenotyping used to detect immune cell types; helper-inducer, cytotoxic-suppressor, natural killer, mature B and T lymphocytes).

Plasma MDMA - MDMA concentration measured with gas chromatography from samples drawn at baseline, and 1.5, 4, 6, 10, 24, 25.5, 28, 30, 48, 54 and 72 h post-drug.

Plasma Cortisol - Using same set of samples described above (Plasma MDMA), performed a fluorescence polarization immunoassay (FPIA), with assay sensitivity set at .45 Ug / dL.

Analyses: Values for lymphocyte subsets, plasma cortisol concentrations and were transformed into differences from baseline, and maximum change from baseline was calculated for these variables. AUC was calculated for CD4 cell, NK cell and MDMA concentrations via trapezoidal rule. Data was apparently analyzed across condition (at least MDMA-placebo, MDMA-MDMA) via one-way ANOVA, with drug 2 (placebo or MDMA) serving as between subjects or within-subjects factor. Post-hoc comparisons were made via Tukey's test and p. was set at 0.05.

Results: Immunological Effects - The immunological effects of Dose 1 were comparable to those reported for Dose 1 in Study 1 (described above); decreased CD4 count, and increased NK cell count, with all values returning to baseline at 24 h. When compared with placebo administered 24 h after Dose 1, a second dose of MDMA (24 h after first dose) produced the same immunological changes produced by the first dose. Changes in CD4 and NK cell count were significantly greater after Dose 2 when compared with Dose 1. The immunological changes produced after Dose 2 also lasted longer, with residual decreased CD4 count remaining 48 h after the second dose of MDMA (54 h after Dose 1).

Plasma Cortisol - Both the first and the second dose of MDMA produced an increase in plasma cortisol values, with cortisol rise peaking 2 h post-drug in both cases. Cortisol rise after second dose of MDMA (24 h post first dose) was not significantly greater or lesser than the rise produced by the first dose. Plasma MDMA - AUC for second dose of MDMA was greater than the AUC for the first dose (0.5 times greater than dose 1).

Overall Effects: When a second dose of 100 mg MDMA was administered 24 h after an initial dose of 100 mg MDMA, the immunological changes it produced were greater than changes produced after a single dose of MDMA. There was a greater decrease in CD4 cells and a greater increase in NIK cells. In addition, the immunological effects lasted longer after the second dose than they did after the first dose, with decreased CD4 cells and increased NK cells still detectable 48 h after Dose 2 (54 h after Dose 1). MDMA concentration in plasma was higher for the second dose than it was for the first dose. While both doses produced a rise in plasma cortisol, the increase produced by the second dose of MDMA was no greater than that produced by the first dose.

Adverse Effects: None reported besides changes in cell mediated immune responses.

Comments: The findings reported in the second study replicate and extend those found in the first study. Because changes appearing after the second dose are greater and last longer than those produced by the initial dose, it appears that administering a second dose of MDMA 24 h after an initial dose may increase vulnerability to infectious disease. It is interesting that administering the same amount of MDMA only 4 h after an initial dose does not produce as dramatic changes that appear after MDMA was readministered 24 h later, implying that short-term tolerance after repeated MDMA administration is time dependent even within a short timespan (4 versus 24 h). The same limitations affecting Study 1 (small sample size, all male participants) are shared by Study 2.