Cannabis May Suppress Immune System
A new study has discovered how marijuana use can suppress the body’s immune functions. Dr. Prakash Nagarkatti from the University of South Carolina and colleagues wanted to research cannabinoids, a group of compounds inside the cannabis plant (including THC, the active ingredient in marijuana), which is already being used for medical purposes such as pain relief. Their study examined why marijuana users are more susceptible to certain cancers and infections.
Dr. Nagarkatti said that cannabis is already believed to suppress immune functions, and that they believe the key to this suppression is a unique type of immune cell, which was recently identified as myeloid-derived suppressor cells, or MDSCs.
Although most immune cells protect the body against infections and cancer, MDSCs actively suppress the immune system, making people more susceptible to disease. People with cancer are known to have an increase in MDSCs, and it is believed that MDSCs may actually promote cancer growth.
The researchers found that cannabinoids can trigger a great amount MDSCs by activating cannabinoid receptors. For the first time, they discovered that cannabinoids may suppress the immune system by activating the MDSCs.
Dr. Nagarkatti said that MDSCs seem to be important cells that may be activated by cancer cells or cannabinoids.
A previous study from the Institut Pasteur in Paris found that cancer cells can produce a molecule called interleukin-1 β (IL-1β), which also activates MDSCs. This study examines how cancer-produced MDSCs also weaken the ability of the immune system to kill cancer cells.
Source: Science Daily, How Cannabis Suppresses Immune Functions: Cannabis Compounds Found to Trigger Unique Immune Cells Which Promote Cancer Growth, November 26, 2010
