Marijuana use suppresses immune functions, study shows

( -- Smoking marijuana can trigger a suppression of the body’s immune functions, making cannabis users more susceptible to certain types of cancers and infections, according to a new study led by a University of South Carolina researcher.

The findings also point to the possibility of using compounds found inside the cannabis plant, which is currently used legally in some places for medical purposes such as pain relief, as a treatment for a large number of additional clinical disorders that benefit from a suppressed immune response, including arthritis and multiple sclerosis.

The team of immunologists, led by Dr. Prakash Nagarkatti of the USC School of Medicine, published their findings in this month’s European Journal of Immunology. Their work focused on cannabinoids, a group of compounds found inside the cannabis plant, including THC (delta-9 tetahydrocannabinol).

“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,” 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 . 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. 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,” said Nagarkatti, the Carolina Distinguished Professor in the department of pathology, microbiology and immunology at the School of Medicine.

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,” he said. “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,” Nagarkatti said. “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.”

Provided by University of South Carolina
Citation: Marijuana use suppresses immune functions, study shows (2010, December 3) retrieved 14 October 2019 from
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Dec 03, 2010
Note that he says: "We believe" therefore he does not know.

Just another crappy article.

Dec 03, 2010
In what manner was the THC administered? Smoking is dangerous.

Dec 04, 2010
which cancers?

Dec 04, 2010
Cannibinoids are a anti-inflammatory, inflammation is a immune response, ofcourse if you have tumors your immune system is suppressed or you would attack yourself...

Do they factor in that cannibinoids repair several genes which operate as the mechanism for cellular apoptosis- the ultimate resolution for cancer. Or that these tumor suppressants work on 100% of cancers, and 50% of all types of tumors. Lets also discount the immediate vaso-constriction response and longterm reversal of blood vessel growth in tumors while doing the complete opposite in every organ of the body when faced with the opposite dilemna (glaucoma, damage hearts) This is a spin study that only forms another hypothesis for a problem already well studied.

Dec 04, 2010
And incase anyone is wondering why it works on 100% types of tumors but not cancer, a lone cancer cell can still maintain its tolerances in a safe level by sharing waste balances with neighboring healthy cells, that fools cellular governors into thinking things are running right. Cannibinoids cannot do it all alone, but they are doing far more good then the harm from smoking it, particularly with the delivery method flooding any part that might be at risk from burnt organics. Especially compared to most modern pharmaceuticals.

Dec 04, 2010
A little bit of knowledge is a dangerous thing
THC is the agonist and suppresses the immune system.
CBD is the antagonist and increases the immune response.
A well balanced properly cured plant has both.
Cannabis modulates most of the bodies systems to achieve homeostasis.
The original author would do well to "read and learn" before spouting off about something they know little about.
Propaganda for war is not science.

Dec 05, 2010
Wow. This is really bad science. All the mice they used in this study "MDSC in TLR4 mutant C3H and C57BL10/ScN" contain mutations in a specific LPS signaling gene that alters and disables large chunks of their immune system. The study didn't use any wild type mice without these mutations to determine how it affected normal mice. Not to even mention the problem of extrapolating this to humans. These mice have difficulty mounting immune responses to many gram negative bacteria. The mutation was found to increase their resistance to certain endotoxins... but this is only because it destroys a chemical pathway that competed with their ability to properly utilize cysteine... which im *guessing* leads to higher glutathione levels. Regardless these are not normal mice.

So mice with genetically mutated immune systems show weird immune activation when given THC ? How does any of this matter to us.

You can go to jax . org and lookup their mice database to find all the mutations.

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