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

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.

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

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 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.

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.