Fig. 4

Summary of how cannabis products may impact the pulmonary immune system. Smoking cannabis increases inflammation in the lungs that is typified by increased neutrophils and macrophages. Mechanistically, the direct impact of the cannabinoids THC and CBD on various immune populations is shown although whether these are also impacted in the lungs from inhaled cannabis products is not known. Generally, cannabinoids are immunosuppressive, and prevent cytokine production, proliferation and cell-specific functions (e.g., phagocytosis, antibody production). In some cases, cellular differentiation to a more suppressive phenotype (e.g., Tregs) is observed. The functional consequence of these immunological changes is not known but is theorized to contribute to chronic lung disease development including lung cancer and COPD. The impact on respiratory infections is inconclusive. It is also not known the impact of vaporized cannabis products, including the inhalation of distillates using an e-cigarette. More research is needed to understand the evolving and complex interaction between inhaled cannabis products and the pulmonary immune system