Chaillon, A. et al. Effect of Cannabis Use on Human Immunodeficiency Virus DNA during Suppressive Antiretroviral Therapy. Clin Infect Dis. 2020 Jan 1; 70(1):140-143. doi: 10.1093/cid/ciz387.

Cannabis use is common in the United States, both for medicinal and recreational use, although availability and legality may vary, depending on one’s state of residence. There have been a number of small studies looking at the effects of cannabis on adherence to ART, retention in care, viral suppression and inflammation. This study looked at the effect of cannabis on viral decay and transcriptional activity of the HIV reservoir in patients on suppressive ART. It included 48 MSM from a primary HIV infection research consortium in San Diego. The authors used three validated questionnaires to screen for drug use, which generated four groups: (1) No drug use; (2) Cannabis use only; (3) Use of other drugs; (4) Use of cannabis and other drugs. Of the 48 subjects, 21% reported no drug use, 11% used cannabis only, 33% used drugs other than cannabis, and 35% used cannabis plus other drugs. HIV-DNA was extracted from four samples of peripheral blood mononuclear cells (PBMCs) and plasma collected over a median of 22 months following initiation of ART. The cannabis-only users had significantly greater HIV DNA levels at baseline but had more rapid HIV DNA decay on ART compared to participants with no drug use or those who used other drugs with cannabis. Use of cannabis alone did not influence cell-associated HIV RNA transcription or cellular activation while on ART. Use of other drugs was associated with increased CD8+ T cell activation and with increased cellular HIV RNA transcription during ART.

Author’s Commentary:

The results of this study are consistent with a previous report that found cannabis use was associated with lower plasma viral loads in persons recently infected with HIV. There is also in-vitro data showing a reduction of HIV replication in the presence of cannabinoids. The mechanisms by which cannabis affects the HIV reservoir remain uncertain and more studies are needed to answer these questions. These findings may ultimately have positive clinical implications but also reaffirm the need for regular screening for substance use in HIV clinical settings. We should also openly share with our patients what the “science” currently tells us regarding substance use and HIV-disease.