Cannabis damages immune cells, raising health concerns for regular users

Cannabis use is increasingly common in Canada and beyond, but its effects on immune function remain poorly understood. This study examined how cannabis joint extract (CJE) affects natural killer (NK) cells, which are crucial immune cells that help protect the body against infections and abnormal cells. Researchers exposed human immune cells to various concentrations of cannabis extract and tracked what happened to the NK cells using advanced flow cytometry analysis. The results were concerning: cannabis exposure caused dose-dependent damage to NK cells, with cells showing signs of stress at concentrations as low as 3 μg/mL.

The research revealed that cannabis impairs NK cells through multiple biological pathways. At the cellular level, CJE triggered increased reactive oxygen species (ROS) production, activated autophagy (a cellular self-cleaning process), reduced mitochondrial membrane potential, and activated caspase-3 leading to programmed cell death (apoptosis). The study also documented DNA damage in exposed NK cells. Functionally, the most significant finding was that cannabis-damaged NK cells lost their ability to kill infected or abnormal cells, a critical immune function measured using HeLa cancer cells in the study. Interestingly, the cells' ability to migrate and adhere to tissues remained intact despite their reduced killing capability.

These findings suggest that regular cannabis use could potentially impair immune surveillance, making the body less capable of fighting off infections and detecting early cancer development. This is particularly important given NK cells' role in first-line immune defense and cancer prevention. While the study used cannabis extract rather than isolated cannabinoids, it provides direct evidence that whole cannabis products can negatively affect immune function through stress-induced cellular mechanisms.