COCAINE AND INTENSITY OF H.I.V. ARE RELATED IN A STUDY OF MICE

Research in mice may help explain something that doctors have noticed in
people who are infected with H.I.V.: cocaine use seems to make the disease
progress faster and lead to more of the opportunistic infections that are
the hallmark of AIDS.

The reason is not known. Drug abusers often eat poorly, have unprotected
sex and neglect their health in other ways, so it has been impossible to
tell whether their problems are due to cocaine itself or to the other
habits that often go with addiction.

A new study suggests that cocaine is to blame. In the study, by researchers
at the AIDS Institute at the University of California at Los Angeles,
specially bred mice were inoculated with human cells and with H.I.V., the
virus that causes AIDS, and then given injections of either cocaine or a
salt-water placebo. Cocaine greatly enhanced replication of the virus and
increased the number of human cells it infected and killed.

Dr. Gayle C. Baldwin, who directed the study, said, "We're talking about a
200-fold increase in viral load in these animals. That is a lot."

In addition, Dr. Baldwin said, the mice given cocaine had only one- ninth
as many CD4 cells as the mice given salt water. CD4 cells, also called
helper T cells, help to activate other cells of the immune system. They are
the prime targets of the AIDS virus, and when they are wiped out, the
ability to fight off infections is lost.

The virus also infects other cells, and, Dr. Baldwin said, "We're seeing
that the population of cells that are not killed off are churning out
incredible amounts of virus."

Why that occurs is not known, she said, adding, "We're working on that
right now."

Dr. Baldwin said that cocaine had powerful effects on both the nervous
system and the immune system, and that it caused the body to produce
steroid hormones and other substances that might affect H.I.V. and its
ability to invade cells.

A report on the study will be published in the March issue of The Journal
of Infectious Diseases and is being posted today on the Internet at
www.journals.uchicago.edu/JID/journal.

Dr. Warner C. Greene, director of the Gladstone Institute of Virology and
Immunology at the University of California at San Francisco, who was not
involved in the study, said doctors had wondered why cocaine users had a
worse course with H.I.V.

"The beauty of this study," Dr. Greene said, "is that it really focuses in
and reveals some specific effect of cocaine. One clearly sees that cocaine
is doing something to the infection process."

Dr. Greene also said he thought the study would enhance both doctors' and
patients' awareness of cocaine's potential to accelerate the course of
H.I.V. infection.

"I think it has very significant implications for people infected with
H.I.V.," he said.

Dr. Baldwin said that even though the study was done in mice, she thought
the findings would apply to people.

"There's always controversy with animal models," she said. "But among
people who do H.I.V. research, this is an accepted model. You can't address
these questions in a human population. It would be unethical. This model
offers us something nothing else really can."

Dr. Greene said, "It's a model, but, boy, the effects they saw were
significant."

The mice in the study were inoculated with human cells because mouse cells
do not become infected with H.I.V. The mice in the study lacked immune
systems, and so would not reject human cells. The mice could then be
injected with H.I.V.