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Effects of delta-9-tetrahydrocannabinol on human immune function and host defense

2002; Elsevier BV; Volume: 121; Issue: 1-2 Linguagem: Inglês

10.1016/s0009-3084(02)00159-7

1873-2941

Michael D. Roth, Gayle Cocita Baldwin, Donald P. Tashkin,

Sleep and Wakefulness Research

This review examines evidence that Δ9-tetrahydrocannabinol (THC) can regulate and suppress human immune responses. Leukocytes express both cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2), and levels of mRNA encoding for them are increased in peripheral blood leukocytes obtained from marijuana smokers, suggesting cannabinoid receptor activation in vivo. Exposure of human T-cells to THC suppresses their proliferation, inhibits the release of interferon-γ, and skews the balance of T-helper cytokines towards a type 2 response. The majority of these effects are CB2 receptor-dependent. Consistent with an impact of THC on cell-mediated immunity, alveolar macrophages (AMs) recovered from the lungs of marijuana smokers are suppressed in their ability to release pro-inflammatory cytokines and nitric oxide (NO), and kill bacteria. Macrophage function is restored by treatment with interferon-γ, a type 1 cytokine. Habitual exposure to THC appears capable of impacting on human cell-mediated immunity and host defense.