Heavy Cannabis Use Associated with Reduction in Activated and Inflammatory Immune Cell Frequencies in Antiretroviral Therapy-Treated Human Immunodeficiency Virus-Infected Individuals

Background. Cannabis is a widely used drug in the United States, and the frequency of cannabis use in the human immunodefciency virus (HIV)-infected population is disproportionately high. Previous human and macaque studies suggest that cannabis may have an impact on plasma viral load; however, the relationship between cannabis use and HIV-associated systemic in?ammation and immune activation has not been well defned. Methods. Te impact of cannabis use on peripheral immune cell frequency, activation, and function was assessed in 198 HIVinfected, antiretroviral-treated individuals by ?ow cytometry. Individuals were categorized into heavy, medium, or occasional cannabis users or noncannabis users based on the amount of the cannabis metabolite 11-nor-carboxy-tetrahydrocannabinol (THCCOOH) detected in plasma by mass spectrometry. Results. Heavy cannabis users had decreased frequencies of human leukocyte antigen (HLA)-DR+CD38+CD4+ and CD8+ T-cell frequencies, compared to frequencies of these cells in non-cannabis-using individuals. Heavy cannabis users had decreased frequencies of intermediate and nonclassical monocyte subsets, as well as decreased frequencies of interleukin 23- A nd tumor necrosis factor-a-producing antigen-presenting cells. Conclusions. While the clinical implications are unclear, our fndings suggest that cannabis use is associated with a potentially benefcial reduction in systemic in?ammation and immune activation in the context of antiretroviral-treated HIV infection.