Cannabis Use Linked to Changes in Inflammatory Gene Expression in HIV-Positive Immune Cells, But Causal Claims Remain Premature

A small cross-sectional study finds associations between cannabis use frequency and NLRP3 inflammasome mRNA levels in macrophages from people living with HIV, raising important questions about neuroimmune interactions while yielding paradoxical ex vivo CBD results that complicate any straightforward anti-inflammatory narrative.

Why This Matters

Despite effective antiretroviral therapy, people living with HIV continue to experience chronic immune activation that drives neurocognitive decline, cardiovascular risk, and accelerated aging. The NLRP3 inflammasome, a central hub of innate immune signaling, is increasingly recognized as a contributor to this persistent inflammatory burden. Cannabis use is highly prevalent among people living with HIV, often motivated by symptom management, yet whether it meaningfully modulates the very inflammatory pathways driving long-term morbidity remains unclear. Research that rigorously interrogates this intersection is both timely and clinically necessary.

Clinical Summary

Chronic inflammation in people living with HIV (PWH) persists even with viral suppression on antiretroviral therapy, and the NLRP3 inflammasome has emerged as a key driver of this inflammatory state, particularly in monocyte-derived macrophages (MDMs) that serve as long-lived HIV reservoirs. A 2025 cross-sectional study conducted at UCSD by Sanna and colleagues, published in the Journal of Neuroimmune Pharmacology, examined NLRP3, IL1b, and IL18 mRNA expression in MDMs from 65 participants (43 PWH, 22 without HIV), stratified by self-reported cannabis use frequency over six months. The mechanistic premise is that cannabinoids, particularly CBD, may modulate inflammasome signaling through effects on NF-kB and related inflammatory cascades, potentially attenuating the chronic immune activation that underlies HIV-associated neurocognitive disorders.

The study’s most robust finding was that untreated MDMs from PWH exhibited 83% higher NLRP3 mRNA than those from HIV-negative controls, consistent with prior literature. Among PWH, moderate cannabis users showed 61% lower IL1b mRNA compared to cannabis-naive individuals, while daily users showed 64% higher IL18 mRNA than moderate users. However, the ex vivo experiment produced paradoxical results: CBD combined with IL-1-beta stimulation reduced NLRP3 mRNA by 22% but simultaneously increased IL1b mRNA 3-fold and IL18 mRNA 2-fold, directly contradicting a straightforward anti-inflammatory interpretation. The cross-sectional design precludes causal inference, subgroup sizes were small after stratification, no protein-level or functional inflammasome data were collected, and cannabis product characteristics were uncontrolled. The authors appropriately frame this work as hypothesis-generating and call for longitudinal and mechanistic follow-up.

Dr. Caplan’s Take

This study addresses an important question that my patients with HIV ask about regularly: whether their cannabis use is helping or hurting their chronic inflammatory burden. The NLRP3 elevation in HIV-positive macrophages is real, well-established, and clinically significant. The cannabis associations are more intriguing than informative at this point, as the small subgroups, uncontrolled product variability, and mRNA-only endpoints make it impossible to draw directional conclusions. The paradoxical CBD findings, where the target gene goes down but downstream inflammatory mediators go up, should give pause to anyone tempted to prescribe CBD as an anti-inflammatory intervention for this population based on current evidence.

In practice, when patients with HIV ask whether cannabis is reducing their inflammation, I tell them honestly that we do not yet know, and that the biology appears more complex than promotional narratives suggest. I do not discourage cannabis use in patients who find it helpful for symptom management, but I frame it as a symptomatic tool rather than an immunomodulatory therapy. I ensure that any cannabis use is documented, monitored for drug interactions with antiretroviral regimens, and discussed openly so that it becomes part of the clinical picture rather than an unexamined variable.

Clinical Perspective

This study sits squarely in the early, exploratory phase of a research arc that will require considerably more work before informing clinical decisions. The confirmation of elevated NLRP3 mRNA in PWH macrophages adds incrementally to a body of evidence that is already relatively well established. The cannabis use frequency associations are novel but carry the full burden of cross-sectional confounding: cannabis users may differ from non-users in ways that independently affect inflammasome biology, including substance co-use, sleep patterns, stress, and dietary factors. Clinicians should not interpret these associations as evidence that cannabis modulates NLRP3 signaling in any clinically actionable direction.

The ex vivo CBD concentration used (30 micromolar) substantially exceeds physiologically achievable plasma levels from oral or inhaled CBD, limiting translational relevance. Clinicians managing PWH who use cannabis should be attentive to potential interactions between CBD and antiretroviral agents metabolized through CYP3A4 and CYP2C19 pathways, including protease inhibitors and some NNRTIs, as CBD can inhibit these enzymes and alter drug levels. The one actionable step clinicians can take now is to systematically document cannabis use frequency, product type, and route of administration in their PWH patients, building the longitudinal data that cross-sectional studies like this one cannot provide.

Study at a Glance

What Kind of Evidence Is This

This is a hybrid study combining cross-sectional observational analysis with an ex vivo experimental component. Cross-sectional designs sit near the base of the evidence hierarchy for causal inference because they capture a single time point and cannot distinguish cause from consequence. The ex vivo component, while experimentally controlled, uses supraphysiological CBD concentrations and isolated cell systems that do not replicate in vivo conditions. The single most important inference constraint is that neither component of this study can establish whether cannabis use causally modulates inflammasome activity in people living with HIV.

How This Fits With the Broader Literature

The elevated NLRP3 mRNA in PWH macrophages aligns with a growing body of evidence, including work by Chivero and colleagues (2017) demonstrating HIV-driven NLRP3 inflammasome activation in microglia and macrophages, and by Mamik and colleagues (2017) showing inflammasome-mediated neuroinflammation in HIV-associated neurocognitive disorders. The cannabis associations are more novel and less grounded in prior work. While several preclinical studies have reported anti-inflammatory effects of cannabinoids on NLRP3 signaling, most used purified compounds in controlled conditions rather than examining real-world cannabis use patterns. The paradoxical ex vivo finding, in which CBD reduced NLRP3 mRNA while simultaneously increasing downstream cytokine mRNAs, does not have a clear parallel in the existing literature and may reflect cell-type-specific or context-dependent effects that require dedicated mechanistic investigation.

Common Misreadings

The most likely overinterpretation is to conclude that cannabis use reduces HIV-associated inflammation by modulating the NLRP3 inflammasome. This exceeds the evidence in several ways. The associations between cannabis use frequency and cytokine mRNA are correlational, not causal, and the directionality is inconsistent across genes: moderate use was associated with lower IL1b but daily use with higher IL18. Furthermore, the ex vivo CBD results actually showed increased downstream inflammatory gene expression alongside the modest NLRP3 reduction, which is the opposite of what a clean anti-inflammatory effect would look like. Readers should also avoid equating mRNA changes with protein-level or functional inflammasome activity, as these relationships are not linear.

Bottom Line

This study confirms that NLRP3 inflammasome gene expression is elevated in macrophages from people living with HIV and generates preliminary associations between cannabis use frequency and related cytokine mRNA patterns. It does not establish that cannabis or CBD reduces HIV-associated inflammation. The paradoxical ex vivo findings and the inherent limitations of the cross-sectional design mean this work is best understood as hypothesis-generating, identifying questions worth pursuing through longitudinal studies with functional endpoints rather than offering evidence that should change clinical practice today.

Frequently Asked Questions

Does this study prove that cannabis reduces inflammation in people with HIV?

No. The study found correlations between cannabis use frequency and certain inflammatory gene expression levels, but the cross-sectional design cannot determine cause and effect. The associations were also inconsistent across different genes, and the laboratory experiment with CBD produced mixed results that included increases in some inflammatory markers. Much more research is needed before any claims about cannabis reducing HIV-related inflammation can be supported.

Should I start using CBD to target the NLRP3 inflammasome if I am living with HIV?

There is no evidence from this study to support using CBD specifically to modulate inflammasome activity. The CBD concentration used in the laboratory experiment was far higher than what can be achieved in the human body through typical oral or inhaled dosing. Additionally, the CBD treatment unexpectedly increased expression of two downstream inflammatory genes even while modestly reducing the NLRP3 gene itself. Any CBD use should be discussed with your HIV care provider, particularly because of potential drug interactions with antiretroviral medications.

What is the NLRP3 inflammasome and why does it matter in HIV?

The NLRP3 inflammasome is a protein complex inside immune cells that acts as a sensor for danger signals and triggers inflammatory responses, including the production of cytokines like IL-1-beta and IL-18. In people living with HIV, even those with well-controlled viral loads on antiretroviral therapy, this inflammasome can remain chronically activated, contributing to ongoing low-grade inflammation that is linked to neurocognitive decline, cardiovascular disease, and other long-term complications.

Why were the results for moderate and daily cannabis users different?

Moderate cannabis users (one to six days per week) showed lower IL1b gene expression compared to non-users, while daily users showed higher IL18 gene expression compared to moderate users. The study cannot explain why these patterns diverge, and several possibilities exist, including dose-dependent biological effects, differences in cannabis product types used by each group, or confounding factors such as other health behaviors that differ between moderate and daily users. These divergent findings underscore the complexity of the relationship and the need for controlled studies.

How large was this study, and does that affect how much we should trust the results?

The total study included 65 participants, which is a reasonable starting point for

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