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Marijuana Ingredient Kills Herpes Viruses in Test-Tube Study

May 15, 1990 GMT

LOS ANGELES (AP) _ Marijuana’s active ingredient killed herpes viruses in test-tube experiments, but smoking pot won’t help people with herpes and might make them prone to other diseases or cancer, a scientist said Monday.

University of South Florida microbiologist Gerald Lancz said his study may help scientists discover new anti-herpes medicines. But he warned that people with oral or genital herpes would be badly misguided if they used the findings to justify smoking marijuana, which has other harmful effects and is illegal.

″Smoking pot is not going to help your herpes, and it could make things a lot worse,″ said Lancz, who presented his findings Monday during the annual meeting of the American Society for Microbiology in Anaheim.

Having the drug in the bloodstream won’t treat herpes sores because the concentration would be too low, Lancz said in a telephone interview.

Other studies suggest marijuana’s active ingredient - delta 9 tetrahydrocanna binol, or THC - might harm the body’s disease-fighting immune system, although the evidence is inconclusive, he said.

Lancz also speculated that if THC is able kill herpes viruses in people, the inactivated viruses might increase the person’s vulnerability to cancer. In previous test-tube experiments, scientists have found that inactivated herpes viruses can convert healthy cells into cancer cells, he said.

″It sounds like this guy wants to show something bad (about marijuana) at all costs,″ said Ronald Alkana, a professor of pharmacology and toxicology at the University of Southern California.

″But he’s showing it (THC) has some antiviral potential,″ Alkana said. ″Whether or not it might help in treatment of human herpes is unknown at this time.″

Alkana called the study ″exciting″ because it means ″the THC molecule might hold a key for developing more effective treatments for herpes.″

Lancz said it might be possible to find substances related to THC that don’t affect the mind but do kill viruses.

Lancz and his colleagues incubated THC and various viruses in test tubes. They found that, in doses somewhat higher than found in the blood of regular marijuana users, THC killed herpes simplex virus 1, which causes the cold sores that typify oral herpes.

The scientists didn’t test THC against herpes simplex 2, the genital herpes virus. But Lancz said the drug almost certainly will kill the genital herpes virus because it is so similar to the oral herpes virus.

The study found THC also killed cytomegalovirus, a herpes virus that causes flu-like symptoms in adults and is the most common infectious cause of birth defects in the United States.

But ″even if smoking marijuana helped control herpes, the costs of marijuana smoking - getting busted and losing your job, for one thing - certainly overshadow any of the potential benefits of treating herpes,″ said Ronald K. Siegel, a psychopharmacologist at the University of California, Los Angeles.

He added that marijuana causes lung problems and there’s good evidence it causes changes in hormones and behavior, including reducing motivation.

In another test-tube study, scheduled for presentation at the microbiology meeting on Tuesday, University of South Florida microbiology student Kirk Trisler found THC suppressed the normal growth of disease-fighting white blood cells and disrupted their ability to kill tumor cells.

A number of previous studies have shown THC can impair the performance of various components of the human immune system, while others have found no such damage. Siegel, Alkana and Lancz agreed there is no evidence demonstrating that pot smokers are more prone to diseases, except for bronchitis and other smoke-related lung problems.