More MS news articles for September 2002

Marijuana use can help rein in runaway immune system

Study: Medicinal use may reduce inflammation of arthritis, Lupus

September 2, 2002 Monday
Tom Spears
Ottawa Citizen

Smoking marijuana several times a week leaves a lasting effect on a healthy person's immune system, a new study from Florida says. But this may actually boost opportunities for the medical use of marijuana.

The effect of marijuana smoking suppresses the immune system by altering the molecules on the outside of some of our cells, and suppresses inflammation at the same time. This could be a useful tool in combatting diseases where the immune system runs out of control and causes painful, and sometimes dangerous, inflammation in our bodies, scientists at the University of South Florida and the University of California, Los Angeles (UCLA).

Arthritis is the most common form of inflammation caused by a misdirected immune system. By attacking our own healthy tissue, it causes inflamed and sore joints.

Lupus, though less common than ordinary arthritis, is another condition caused by our immune system attacking our own bodies. People with lupus are given immune-suppressing drugs to fight the disease.

Now Thomas Klein, a professor of medical microbiology and immunology at South Florida, says marijuana may do a similar job.

His study of 10 healthy marijuana smokers, all of whom smoked at least several times a week, and 46 non-drug users found molecules called marijuana receptors were more numerous on marijuana smokers' white blood cells, part of their immune system.

The findings were reported in the Journal of Neuroimmunology

Marijuana's influence on the immune system has been hotly debated. While there's a lack of information on humans, Mr. Klein says animal studies show that marijuana and its psychoactive compounds, known as cannabinoids, suppress immune function and inflammation.

"This suggests marijuana or cannabinoids might benefit someone with chronic inflammatory disease, but not someone who has a chronic infectious disease such as HIV infection," he said.

If that's true, "this property might be harnessed to treat patients with overly aggressive immune responses or inflammatory diseases like multiple sclerosis and rheumatoid arthritis.

"The bottom line is you cannot routinely smoke marijuana without it affecting your immune system," he said. "However, because of the complexity of the immune system, we can't say yet whether the effect we've observed in humans is good or bad."

Receptors are places on the outside of a cell where a chemical such as a drug or hormone can latch on. Receptors that latch to THC, the compound in marijuana that produces a high, have been found in tissues throughout the body and in the brain. In fact, the body also produces a "cannabinoid" chemical similar to THC, which latches on to the same receptors, suggesting that the body's own cannabinoid system plays a role in our immune systems, Mr. Klein said.

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