Review Examines How Inhaled Cannabis Affects Lung Immune Defenses, With More Questions Than Answers | Research

The takeaway

A review of how inhaled cannabis affects pulmonary immunity found cannabinoids generally dampen lung immune function, which could both reduce harmful inflammation and impair defense against infections, but critical knowledge gaps remain.

Pulmonologists, cannabis smokers, vaping researchers, immunologists.

Cannabis dampens lung immune function: beneficial for inflammation, risky for infection defense

What the researchers found

Cannabinoids interact with the endocannabinoid system to generally dampen immune function in the lungs, including reducing inflammatory responses of epithelial cells and alveolar macrophages. This dual effect could be beneficial (reducing chronic inflammation) or harmful (impairing pathogen defense). Alternative delivery methods like vaping may have different immune effects than combustion. The field lacks definitive data on long-term pulmonary immune consequences.

Why it matters

With cannabis inhalation increasing alongside legalization, understanding how it affects the lungs' immune defenses is critical. The respiratory system is the first point of contact for inhaled cannabis, yet we know surprisingly little about how cannabinoids alter its immune function.

The numbers in context

Cannabis use increasing with legalization worldwide. Vaping as an alternative to combustion is growing. Cannabinoids dampen immune function via endocannabinoid system. Effects on epithelial cells and alveolar macrophages documented.

How the study worked

Narrative review of the current literature on inhaled cannabis/cannabinoid effects on pulmonary immune responses, including in vitro, in vivo, and clinical studies.

What this study cannot tell us

Narrative review without systematic methodology. Much of the evidence is preclinical. Long-term human data on pulmonary immune effects of cannabis is lacking. Difficult to separate combustion byproduct effects from cannabinoid effects.

How to read the evidence

Narrative review identifying a critical knowledge gap, with most evidence from preclinical studies.

When this study was published

Published 2023.

The bigger picture

The tension between beneficial anti-inflammatory effects and potentially harmful immune suppression is the central challenge. For someone with asthma, dampened lung inflammation might help. For someone exposed to respiratory pathogens, the same dampening could increase infection risk.

Questions still open

Does cannabis vaping have different pulmonary immune effects than smoking?
Are regular cannabis smokers at higher risk for respiratory infections?

Common questions

Does smoking cannabis affect lung immunity?

This review found cannabis generally dampens immune responses in the lungs, which could reduce inflammation but also weaken defense against infections. Definitive long-term data is lacking.

Is vaping cannabis safer for the lungs than smoking?

Vaping avoids combustion byproducts, but this review notes that cannabinoid effects on pulmonary immunity would still occur regardless of delivery method. More research is needed.

Read the original research

Modulation of pulmonary immune function by inhaled cannabis products and consequences for lung disease.

Respiratory research, 24(1), 95

View on PubMed ↗Publisher’s paper ↗

Citation

Preteroti, Matthew; Wilson, Emily T; Eidelman, David H; Baglole, Carolyn J. (2023). Modulation of pulmonary immune function by inhaled cannabis products and consequences for lung disease.. Respiratory research, 24(1), 95. https://doi.org/10.1186/s12931-023-02399-1