Cannabis-Using HIV Patients Had Lower Levels of Inflammatory Immune Cells | Research

The takeaway

HIV-infected cannabis users had lower levels of circulating inflammatory CD16+ monocytes and the inflammatory marker IP-10 compared to non-using HIV patients, and THC directly suppressed these markers in lab experiments.

HIV researchers, immunologists, medical cannabis researchers.

Cannabis users' monocytes were resistant to inflammatory activation, unlike monocytes from HIV+ non-users which showed pronounced inflammatory response.

What the researchers found

HIV+ cannabis users had lower circulating CD16+ monocytes and plasma IP-10 (both implicated in HIV-associated neuroinflammation) compared to HIV+ non-users. In-vitro THC treatment impaired the transition of monocytes to the inflammatory CD16+ state and reduced IP-10 production, confirming a direct anti-inflammatory effect.

Why it matters

HIV-associated neuroinflammation, driven partly by activated monocytes, contributes to cognitive decline even in patients on antiretroviral therapy. If cannabis can reduce this inflammatory process, it could help protect against HIV-related brain damage.

The numbers in context

HIV+ cannabis users had lower CD16+ monocytes and plasma IP-10. Monocytes from cannabis users were resistant to IFN-alpha-induced CD16 upregulation, while monocytes from non-users showed pronounced CD16 induction.

How the study worked

Compared circulating CD16+ monocyte levels and plasma IP-10 between HIV+ cannabis users and non-users using flow cytometry. In-vitro experiments with THC on isolated blood cells confirmed direct effects on monocyte activation and IP-10 production.

What this study cannot tell us

Observational comparison; cannabis users may differ from non-users in other ways. Cannabis users' exposure varied in dose and duration. In-vitro THC concentrations may not reflect physiological levels.

How to read the evidence

Moderate - combines observational data with mechanistic in-vitro confirmation, though sample sizes were modest.

When this study was published

Published in 2018. Research on cannabis and HIV-related inflammation continues.

The bigger picture

Despite effective antiretroviral therapy, chronic immune activation remains a problem in HIV. This study suggests cannabinoids may modulate one of the key inflammatory pathways implicated in HIV-associated neurocognitive disorders.

Questions still open

Could cannabinoids serve as adjunctive therapy to reduce neuroinflammation in HIV? What dose and duration of cannabis use is needed for these anti-inflammatory effects? Does this translate to measurable neuroprotection?

Common questions

Can cannabis reduce HIV-related brain inflammation?

This study found that HIV patients who used cannabis had lower levels of CD16+ monocytes and IP-10 - both markers of the neuroinflammation that contributes to cognitive decline in HIV. Lab experiments confirmed THC directly suppressed these inflammatory markers.

How does THC affect the immune system in HIV?

THC appeared to prevent monocytes from transitioning to an activated, inflammatory state (CD16+) and reduced production of the inflammatory protein IP-10. Both are implicated in HIV-associated neuroinflammation.

Read the original research

HIV-infected cannabis users have lower circulating CD16+ monocytes and IFN-γ-inducible protein 10 levels compared with nonusing HIV patients.

AIDS (London, England), 32(4), 419-429

View on PubMed ↗Publisher’s paper ↗

Citation

Rizzo, Michael D; Crawford, Robert B; Henriquez, Joseph E; Aldhamen, Yasser A; Gulick, Peter; Amalfitano, Andrea; Kaminski, Norbert E. (2018). HIV-infected cannabis users have lower circulating CD16+ monocytes and IFN-γ-inducible protein 10 levels compared with nonusing HIV patients.. AIDS (London, England), 32(4), 419-429. https://doi.org/10.1097/QAD.0000000000001704