Cannabis does not reduce T cells in people living with HIV
Kirk Taylor, HIV i-Base
A cross-sectional study published in the Journal of Infectious Diseases reports no link between cannabis use and altered T cell count or function in people living with HIV who reported modest use compared to matched non-users. 
Effects of occasional cannabis use upon T cell count immunological parameters for people living with HIV (n=75) were studied. Median time since diagnosis was 12 years (range: 2 to 34 years), and participants were female (20%), Black (69%) and median age was 43 years (range: 33 to 53 years).
Cannabis use was defined by positive urine test plus self-reported use for over 12 days in the past three months. Cannabis users (n=33) were compared with matched controls (n=42).
Cannabis use did not alter the total number of CD4 or CD8 T cells, nor did it impact their immunological response. Cannabis use was linked to lower levels of exhausted and senescent T cells, without altering the response to HIV.
Longitudinal studies are needed to fully evaluate the impact on the viral reservoir.
It is important to note that the results nfrom this study are a small aspect of safety.
Harms of smoke inhalation have also been reported by other studies.
A recent US study also reported higher levels of metals in smokers, though data are not available for other ways of using marijuana. 
The benefits reported from marijuana use individualises the benefit:risk decision.
- Falcinelli SD et al. Impact of cannabis use on immune cell populations and the viral reservoir in people with HIV on suppressive therapy. Journal of Infectious Diseases. 22 August 2023. DOI: 10.1093/infdis/jiad364. (22 Aug 2023).
McGraw KE et al. Blood and urinary metal levels among exclusive marijuana users in NHANES (2005–2018). Environmental Health Perspectives. DOI: 10.1289/EHP12074. (30 August 2023).