Immunomodulating properties of gamma-hydroxybutyrate (GHB), flunitrazepam and ethanol in 'club drugs' users.

Despite the increasing concern about gamma-hydroxybutyrate (GHB) toxicity in users, no studies have addressed GHB and other club drugs effects on the immune system under controlled administration. Lymphocyte subsets and functional responsiveness of lymphocytes to mitogenic stimulation were measured in 10 healthy male recreational users of GHB who participated in five experimental sessions within the framework of a clinical trial. The study was randomized, double blind, double dummy and cross-over. Drug conditions were: a single oral dose of GHB (40 mg/kg or 60 mg/kg), ethanol (0.7 g/kg), flunitrazepam (1.25 mg) and placebo. Acute GHB produced a time-dependent immune impairment in the first 4 hours after drug administration associated with an increase in cortisol secretion. Although total leukocyte count remained unchanged, there was a significant decrease in the CD4 T/CD8 T-cell ratio, as well as in the percentage of mature T lymphocytes, probably because of a decrease in both the percentage and absolute number of T helper cells. A significant decrease was also observed in natural killer cells and in functional responsiveness of lymphocytes to mitogenic stimulation. Flunitrazepam administration did not produce any change in the immune system, while ethanol intake produced a decrease in B lymphocytes and in lymphocyte proliferative response to mitogens. These results provide the first evidence that GHB intake under a controlled environmental setting impairs the immunological status and confirms the alterations in the immune function caused by ethanol.