Compounds found in the cannabis plant can trigger a suppression of the body’s immune functions, creating greater susceptibility to certain types of cancers and infections, according to research led by the eminent immunologist
Dr. Prakash Nagarkatti at the University of South Carolina School of Medicine.
The findings also point to the possibility of using such compounds, currently used legally in some places for pain relief and other medical purposes - as a treatment for a large number of additional clinical disorders that benefit from a suppressed immune response, including importantly rheumatoid arthritis, multiple sclerosis and lupus.
The research, published in the European Journal of Immunology, focuses on a group of cannabinoid compounds, including THC (delta-9 tetahydrocannabinol).(1)
“Cannabis is one of the most widely used drugs of abuse worldwide, and it is already believed to suppress immune functions making the user more susceptible to infections and some types of cancer,” Dr. Nagarkatti said.
“We believe the key to this suppression is a unique type of immune cell, which has only recently been identified by immunologists - called myeloid-derived suppressor cells, MDSCs.”
• While most immune cells fight against infections and cancers to protect the host, MDSCs actively suppress the immune system.
• The presence of these cells is known to increase in cancer patients,
• And it is believed that MDSCs may suppress the immune system against cancer therapy, actually promoting cancer growth.
Dr. Nagarkatti’s team demonstrated that cannabinoids can trigger a massive number of MDSCs through activation of cannabinoid receptors.
“Our research for the first time demonstrates that marijuana cannabinoids can activate a unique type of immune cell, and the job of these cells is to suppress the immune response,” he says.
Suppressing the immune response is important for treating a large number of ailments, including arthritis, multiple sclerosis, lupus and allergies.
“In these, your immune system gets activated and starts destroying your own cells and tissues. You have to try to suppress your immune response,” Dr. Nagarkatti explains. “In such instances, there is a need to develop drugs that can suppress the immune response.”
“Marijuana cannabinoids present us with a double-edged sword,” he adds. “On one hand, due to their immunosuppressive nature, they can cause increased susceptibility to cancer and infections. However, further research of these compounds could provide opportunities to treat a large number of clinical disorders where suppressing the immune response is actually beneficial.”
The research was funded by the National Institutes of Health’s National Institute on Drug Abuse. Co-authors were Dr. Venkatesh Hegde and Dr. Mitzi Nagarkatti.
1. See abstract & full text article: “Cannabinoid receptor activation leads to massive mobilization of myeloid-derived suppressor cells with potent immunosuppressive properties.”)
Source: University of South Carolina news release, Dec 2, 2010