New study reveals how cannabis suppresses immune functions

Nov 25, 2010

An international team of immunologists studying the effects of cannabis have discovered how smoking marijuana can trigger a suppression of the body's immune functions. The research, published in the European Journal of Immunology, reveals why cannabis users are more susceptible to certain types of cancers and infections.

The team, led by Dr Prakash Nagarkatti from the University of South Carolina, focused their research on cannabinoids, a group of compounds found inside the cannabis plant, including THC (delta-9 tetahydrocannabinol) which is already used for medical purposes such as pain relief.

"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," said Dr Nagarkatti. "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 , actually promoting cancer growth.

Dr Nagarkatti's team demonstrated that cannabinoids can trigger a massive number of MDSCs through activation of cannabinoid receptors. This research reveals, for the first time, that cannabinoids may suppress the immune system by activating these unique cells.

"These results raise interesting questions on whether increased susceptibility to certain types of cancers or infections caused from smoking marijuana results from induction of MDSCs," said Nagarkatti. "MDSCs seem to be unique and important cells that may be triggered by inappropriate production of certain growth factors by cancer cells or other chemical agents such as cannabinoids, which lead to a suppression of the immune system's response."

In a related study, also published in the European journal of Immunology, Dr Christian Vosshenrich from the Institut Pasteur in Paris, reveals that when cancer cells grow they produce a molecule called interleukin-1 β (IL-1β), which also triggers MDSCs. This study identifies how MDSCs produced during also weaken the ability of to kill .

"Marijuana cannabinoids present us with a double edged sword," concluded Dr Nagarkatti. "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."

Explore further: Growing a blood vessel in a week

More information: Hedge. V, Nargarkatti. M, Nargarkatti. P, “Cannabinoid receptor activation leads to massive mobilization of myeloid-derived suppressor cells with potent immunosuppressive properties” European Journal of Immunology, November 2010. DOI:10.1002/eji.201040667

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User comments : 42

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Ravenrant
4.8 / 5 (12) Nov 25, 2010
"Cannabis is one of the most widely used drugs of abuse worldwide ..."

Abuse? Drugs that are 'abused' hurt people. If marijuana is 'abused', then so is aspirin.

"..due to their immunosuppressive nature, they can cause increased susceptibility to cancer and infections."

What about the fact that after all these years there is no evidence of marijuana causing emphysema or cancer? It didn't take this long to figure out that cigarettes caused emphysema and cancer. Maybe it had something to do with people dying by the thousands and carrying around oxygen bottles by the thousands. I think the pot legalization forces are hiding this evidence.
Bog_Mire
4.9 / 5 (14) Nov 25, 2010
I would say alcohol, then caffeine, then nicotine, then antidepressants, then fox news are far ahead of marijuana in terms of most abused drugs worldwide....what if you use an atomizer? or cookies?
philosothink
5 / 5 (6) Nov 25, 2010
It's funny how universities in states owned by big tobacco find stuff like this, and states where cannabis is again considered a medicine find opposite findings... I'm curious as to whether or not if they ran a parallel study on tobacco?

I doubt it for some reason.
Eikka
1.9 / 5 (14) Nov 25, 2010
Cannabinoids in the plant are by their very purpose a pesticide meant to harm the critter that eats the plant one way or another.

It's crazy to assume no ill effect.
Skeptic_Heretic
4.9 / 5 (14) Nov 25, 2010
Cannabinoids in the plant are by their very purpose a pesticide meant to harm the critter that eats the plant one way or another.
That's not accurate in the least. Cannabinoids serve two functions. They are used in plants and animals as an intercellular signaling system. In plants they're also used as an aromatic to attract pollinators and fertilizers.

Their purpose is the exact opposite of what you suggest.

It's crazy to assume no ill effect.
It's also crazy to assume any effect without research.
ziprar
3 / 5 (5) Nov 25, 2010
We all know that marijuana is harmless, therefore any scientific research that indicates otherwise must be fake or at least biased.
marjon
1.2 / 5 (10) Nov 25, 2010
We all know that marijuana is harmless, therefore any scientific research that indicates otherwise must be fake or at least biased.

If it is harmless, there should be no restrictions on its use by airline pilots or truck drivers or.....
Sancho
4.6 / 5 (8) Nov 25, 2010
Eikka: Would love to see your documentation for the pesticide claim.

As to this "study," the guy shows his bias in using the word "abuse" to describe pot smoking. I first smoked 40 years ago, and my experience, at least, has been far fewer flus and colds since I began. That's not a claim for weed. It's a function, I suppose, of outgrowing the immune system problems of my childhood.

Let's use a little common sense. Marijuana has been widely used for thousands of years. You don't need statistical analysis to know that if it were grossly toxic (everything is potentially toxic), this would be known by now. Tobacco, for example, was known to be dangerous to health within 100 years of its introduction into Europe. So, yeah, this study appears to be propaganda from Corporate Science.


apex01
1 / 5 (6) Nov 25, 2010
Marijuana smoke contains 50-70 percent more carcinogens than tobacco smoke.
Mauricio
4.3 / 5 (4) Nov 25, 2010
Since people who do research do not like to READ!!!!

Here is a video to see if they have time to watch it: (before they go home to watch hours of TV)

http://www.youtub...Q16cGBHU

Cannabis consumption actually reduces the risk of cancer, in other words, exclusive marijuana smokers have a lower risk of cancer than the rest of the population!

EMPIRICALLY INVESTIGATED WITH HUMAN SUBJECTS!

Physphan
4.5 / 5 (4) Nov 25, 2010
Sounds like inappropriate confirmation of the researcher's participatory beliefs to me. Who FUNDED this alleged study? The lead 'researcher' is from a state that grows a LOT of tobacco...hmmmmm.
Ravenrant
5 / 5 (6) Nov 25, 2010
Cannabinoids in the plant are by their very purpose a pesticide meant to harm the critter that eats the plant one way or another.

It's crazy to assume no ill effect.


Would be crazy, if it were a pesticide. Pesticides kill bugs. The THC present in the small mushroom like structures on the seed pods are a repellent, not a pesticide (mostly repels idiots too).

Marjon, good argument, work for Fox? If not apply, they like people who twist the facts to suit themselves. Who said airline pilots should be allowed to smoke while flying?
Ravenrant
4.6 / 5 (7) Nov 25, 2010
Marijuana smoke contains 50-70 percent more carcinogens than tobacco smoke.


So where is the 50-70% more lung cancer victims? By that statistic it should be epidemic among pot smokers. Know of any lung cancer cases attributed to pot at all? Should be easy to find thousands, plenty of pot smokers don't smoke cigarettes. I know, they are so high they don't know they have lung cancer.
apex01
1.6 / 5 (10) Nov 25, 2010
50-70 percent lung cancer victims are probably cigarette smokers. Every pothead i know smokes tobacco if not more.
apex01
2.5 / 5 (4) Nov 25, 2010
Another problem with Marijuana is that it's extremely hard to regulate/tax. Where as tobacco isn't hard.
retrosurf
not rated yet Nov 25, 2010
From the publication:
Funded by:
National Institutes of Health, USA. Grant Numbers: R01-DA016545, R01-ES09098, R01-AI053703, R01-AI058300, R01-HL058641, P01-AT003961

Alphakronik
5 / 5 (2) Nov 25, 2010
Marijuana smoke contains 50-70 percent more carcinogens than tobacco smoke.


Please give us a reference.
trekgeek1
5 / 5 (7) Nov 25, 2010
We all know that marijuana is harmless, therefore any scientific research that indicates otherwise must be fake or at least biased.

If it is harmless, there should be no restrictions on its use by airline pilots or truck drivers or.....


Nobody is saying it doesn't make you loopy and impair your coordination or reflexes. Supporters of legalization are saying that alcohol does the same thing and can kill someone if they drink too much, yet is legal. You simply mandate that you may not work, drive, or fly a commercial airliner while under its influence, just like alcohol. Do you really misunderstand your opponents position so badly? Or do you just intentionally practice deception?
Ravenrant
5 / 5 (4) Nov 26, 2010
50-70 percent lung cancer victims are probably cigarette smokers. Every pothead i know smokes tobacco if not more.


All of them? Good representative sample I'm sure. Most of the ones I know don't. Some never have.

I assume you meant 60-70% are pot smokers. You think 60-70% of cigarette smokers smoke pot? LOL You should get over your prejudice (obvious since you refer to them as potheads) and look at things objectively, ALL things. You will probably get a new perspective.

http://www.webmd....g-cancer

stealthc
4.7 / 5 (6) Nov 26, 2010
no, I think he meant most weed smokers smoke cigarettes too. An aftertoke is always nice. Of course I would rather get cancer of my own doing and having fun, smoking some nice blueberry pot, versus getting cancer from body scanners, or getting cancer from pharmaceuticals and chemicals contaminating tap water. I think what I do to potentially hurt myself is my personal risk -- a liberty that I take for myself regardless of law. As for the system I have a beef that it does all sorts of things to risk my health and I have no choice in the matter.
Caliban
3.8 / 5 (4) Nov 26, 2010
...and it is already believed to suppress immune functions making the user more susceptible to infections and some types of cancer," said Dr Nagarkatti.


This supposition is used to support the ASSERTION OF CAUSALITY, yet not a single shred of quantitative evidence is cited to back the assertion itself.

At best, this is deeply flawed "research", at worst, outright propaganda. In either case, it deserves nothing less than a quick death and immediate consignment to the dustbin of irrelevant pseudoscience.

Bog_Mire
4 / 5 (3) Nov 26, 2010
speaking of worse ways to get cancer than reefer, how about the ink from the receipt dockets that was on Physorg not long ago. Pity the poor check out chix. Crappy job coupled with handling carginogenic ink all day long. bummer!!! :( I smell a mass lawsuit in the making....any one know a good workers comp lawyer?
Skeptic_Heretic
4.8 / 5 (6) Nov 26, 2010
Marijuana smoke contains 50-70 percent more carcinogens than tobacco smoke.
False.

Or do you just intentionally practice deception?
True.

Marjon does intentionally practice deception.
marjon
1.3 / 5 (6) Nov 26, 2010
Nobody is saying it doesn't make you loopy and impair your coordination or reflexes.

But it causes no harm?
A sit-n-spin will do the same, and a lot cheaper.
StatusLOL
4.6 / 5 (10) Nov 26, 2010
Nobody is saying it doesn't make you loopy and impair your coordination or reflexes.

But it causes no harm?
A sit-n-spin will do the same, and a lot cheaper.


You're obviously sitting here trying to troll a topic you know nothing about. You've made it clear you don't smoke, and thats fine with me, one less idiot to be compared to. But why sit here and argue, poorly I might add, about something you don't even know?

I've been smoking pot for well over 25 years, and I can assure you that a sit-n-spin will not do the same thing. I also wouldn't exactly say that getting high makes me loopy and impairs my coordination or reflexes though either. I get neither loopy nor impaired when I smoke, I get relaxed and inspired, maybe a little sleepy.

So please, let the adults discuss the topic and go on with whatever it is you do.

marjon
1.9 / 5 (8) Nov 26, 2010
I get neither loopy nor impaired when I smoke, I get relaxed and inspired, maybe a little sleepy.

But it does no harm?
I don't really care what anyone smokes or drinks or shoots up.
I don't support taxing those substances to pay for rehab or for any subsequent health effects from using those substances, I don't support using an 'under the influence' excuse when those people cause harm to others.
marjon
1.3 / 5 (6) Nov 26, 2010
"Scientists have identified more than 150 chemicals in marijuana smoke and tar. Marijuana smoke contains cancer-causing chemicals such as benzopyrene, which occurs 70 percent more in marijuana smoke than in tobacco smoke. Examinations of human lung tissue exposed to continuous marijuana smoke in laboratory testing show precancerous cellular change. In laboratory tests, the tars from marijuana smoke produce tumors when applied to animal skin. These studies suggest that prolonged marijuana use causes cancer. "
http://atlantarec...rijuana/
marjon
1 / 5 (3) Nov 26, 2010
"Marijuana smoke has joined tobacco smoke and hundreds of other chemicals on a list of substances California regulators say cause cancer.

Read more: http://www.nydail...6Q2ub0XT
Skeptic_Heretic
4.7 / 5 (6) Nov 26, 2010
"Scientists have identified more than 150 chemicals in marijuana smoke and tar. Marijuana smoke contains cancer-causing chemicals such as benzopyrene, which occurs 70 percent more in marijuana smoke than in tobacco smoke. Examinations of human lung tissue exposed to continuous marijuana smoke in laboratory testing show precancerous cellular change. In laboratory tests, the tars from marijuana smoke produce tumors when applied to animal skin. These studies suggest that prolonged marijuana use causes cancer. "
http://atlantarec...rijuana/

And then all the rest of the research, some of which was posted above, says otherwise. Again, you're wrong.
trekgeek1
4.7 / 5 (6) Nov 27, 2010
Nobody is saying it doesn't make you loopy and impair your coordination or reflexes.

But it causes no harm?
A sit-n-spin will do the same, and a lot cheaper.


I don't know if it does cause harm because I don't smoke it and have had little motivation to research it. But again, cigarettes and alcohol cause health problems, so that isn't the issue. You are always going on about getting government out of our lives, so I would assume you'd be in favor of individuals making their own choice about their own bodies. Let people make adult decisions, right? If they choose to harm themselves,fine.
Ravenrant
3.5 / 5 (2) Nov 27, 2010
"Marijuana smoke has joined tobacco smoke and hundreds of other chemicals on a list of substances California regulators say cause cancer.

Read more: http://www.nydail...6Q2ub0XT


Kneejerk reaction, the chemicals are there ergo it causes cancer. You can't have cause and effect without the effect. I have a beaker of acid and base, you can't draw the conclusion that it is acidic just because there is acid present because the base neutralizes it.
StatusLOL
4 / 5 (3) Nov 27, 2010
"Scientists have identified more than 150 chemicals in marijuana smoke and tar. Marijuana smoke contains cancer-causing chemicals such as benzopyrene, which occurs 70 percent more in marijuana smoke than in tobacco smoke. Examinations of human lung tissue exposed to continuous marijuana smoke in laboratory testing show precancerous cellular change. In laboratory tests, the tars from marijuana smoke produce tumors when applied to animal skin. These studies suggest that prolonged marijuana use causes cancer. "
http://atlantarec...rijuana/


I've heard this bullshit spat out time and time again, and theres one major flaw with it. Just like tobacco, when they did this study on marijuana, they tested the leaves. Now, I personally would never ever in my life like to smoke a pot leaf, and I'm sure most others feel the same way. You smoke the bud. So why would I listen to the test results of the leaf, when I would never even touch it?
rproulx45
5 / 5 (3) Nov 27, 2010
there is something wrong with this study. while the immune function may be suppressed, it does not indicate the pot smoker get sick more or less often. The pot smokers Ive known over the years never impressed me as "sickies", but I admit that is coincidental.
rproulx45
4.5 / 5 (6) Nov 27, 2010
Examinations of human lung tissue exposed to continuous marijuana smoke in laboratory testing show precancerous cellular change.
****
Really? Is that the best you got? Too bad for those "continuous smokers of marijuana". I hate to break this to you, but people die, all the time. It's considered common.It's what you do with life that matters and if smoking marijuana helps a person enjoy their life, I'm all for it.
marjon
1 / 5 (5) Nov 27, 2010
How many marijuana smokers support anti-tobacco smoking laws or laws in schools to restrict certain foods to prevent obesity or....
San Francisco, I suspect, has many marijuana smokers, but support all sorts of other nanny state restrictions.
A govt powerful enough to give you everything is powerful enough to take it away.
Ulg
5 / 5 (7) Nov 28, 2010
Of course cannibinoids throttle the immune system- it is a anti-inflammatory for several diseases, a overzealous immune system only compounds inflammation.

The study obviously has not factored in that cannibinoids correct and engage the p53 gene which causes the secretion of a tumor suppressant vital for apoptosis to occur in 50% of cancer and 100% of tumors.. Nor did they take into account cannibinoids ability to regionally control vascular system, in short term causing vasoconstriction- and longterm reversing abnormal vascular growth in tumors. The study is supported to NIDA- it is rife with confounding factors and at BEST concludes with a hypothesis for a subject that has already been well studied but apparently not yet spinned out.
Mesafina
3.3 / 5 (3) Nov 28, 2010
lets hear it straight Marjon, do you or do you not support ending the prohibition on marijuana?
StatusLOL
5 / 5 (1) Nov 28, 2010
How many marijuana smokers support anti-tobacco smoking laws or laws in schools to restrict certain foods to prevent obesity or....
San Francisco, I suspect, has many marijuana smokers, but support all sorts of other nanny state restrictions.
A govt powerful enough to give you everything is powerful enough to take it away.


I can't even say I know what point you're trying to get across here.
lets hear it straight Marjon, do you or do you not support ending the prohibition on marijuana?


QFT.

Crucialitis
5 / 5 (3) Nov 28, 2010
Y'know.. one could drown in the fountain of youth if they tried hard enough.
Ravenrant
5 / 5 (1) Nov 28, 2010
Excellent point about them testing leaves if it's true. Just goes to show how people will have the results they want and look for a way to produce them, especially if they know the views of those funding them. The only people who smoke the leaves are the poor fools that got/get govt marijuana. I'd like to see a test of Hash, almost no vegetable matter at all.
RaphaelH
5 / 5 (1) Nov 28, 2010
How many marijuana smokers support anti-tobacco smoking laws or laws in schools to restrict certain foods to prevent obesity or....
San Francisco, I suspect, has many marijuana smokers, but support all sorts of other nanny state restrictions.
A govt powerful enough to give you everything is powerful enough to take it away.
------------------------------
I can't believe you would compare smoking marijuana on a volountary basis to unhealty food in schools, kids in school most often don'T have the choice to eat at school because parents are too busy to prepare healty lunch, OBESITY ACTUALLY KILLS PEOPLE, TONS OF THEM THERE IS NO CONTRADICTORY STUDIES, NOT ONE STUDY INDICATES POSITIVE EFFECTS LINKED TO OBESITY, same for tobacco obviously
vonrock
not rated yet Nov 29, 2010
I don't know about you guys, but I burn the shit out of it. those noids don't stand a chance. thanks anyway.