Increasingly, cannabis is being hailed as a wonderdrug- treating ailments from pain to inflammation and even COVID-19. But how does cannabis affect the immune system? And is this affected by how often it is used?
Given historical cannabis legislation, little research exists on the topic. However, as interest and legality in the substance grow, more research is coming to light. And so far, it seems that cannabis may suppress immune function. While this may be helpful for people with autoimmune conditions, it may not be as helpful for those with healthily functioning immune systems.
Cannabis works via the body's endocannabinoid system (ECS), considered to be a gatekeeper of the immune system due to its ability to modulate inflammatory responses. Within the system, components of cannabis bind to both CB1 and CB2 receptors to produce different effects.
A review from 2020 found that cannabidiol (CBD) suppresses the activation of various immune cells and induces death in others. This anti-inflammatory response is not always negative as it can be used to control excessive inflammation like cytokine storms seen in severe cases of COVID-19 or patients with autoimmune disease. Tetrahydrocannabinol (THC) also seems to suppress immune activity abd may additionally change the function of certain antimicrobial immune cells.
While cannabis's immunosuppressive properties may be beneficial for those who need them, for those without immuno-irregularities, it may be problematic. Research from 2003, for example, found that cannabis users had significant reductions in white blood cell functionality (decreasing the body's ability to fight infections) when compared to non-users. Regular users also had decreased amounts of natural killer cells, which limit the spread of tumors and microbial infections.
These effects can be especially negative for those who are already immuno-compromised. While cannabis has been shown to potentially ease pain associated with chemotherapy, it has also been shown to significantly decrease quantities of infection-fighting cells in people undergoing the therapy. This may further complicate symptoms while using the treatment.
The same, however, is not necessarily true for those with HIV and AIDS. Although people with these conditions are also immunocompromised, research instead suggests that cannabis may enhance their immune systems, as noted by an observed increase in CD4 cells (a biomarker for a robust immune system) and a decrease in viral load.
All in all, while cannabis may generally have an immuno-suppressive effect, it seems that in some cases, such as with HIV and AIDS, it may enhance immune function. Moreover, as it produces some positive effects beyond immunomodulation such as pain relief, physicians may weigh up the costs and benefits of its effects before prescription on an individual patient basis, especially until more research emerges.
Sources: Leafly, Marihuana and Medicine, JAMA, NIH