STUDY MAY EXPLAIN WHY USERS OF COCAINE GET SICK SO OFTEN

Addiction specialists at Harvard University think they have found one
reason that cocaine users seem to get sick so often: The drug restricts
production of a body protein that triggers immune responses.

Doctors have often noted that cocaine users suffer more infections,
including the AIDS virus. One theory holds that this is because cocaine
users are more likely to engage in dangerous behavior such as unsafe sex.

But a study published in this month's Journal of Clinical Endocrinology and
Metabolism suggests that cocaine also has a direct effect on the body's
infection-fighting chemistry.

John Halpern and colleagues at McLean Hospital and Harvard Medical School
gave an injection of either cocaine or a placebo to a human volunteer in
one arm while placing a catheter in the veins of the volunteer's other arm.

Normally, the presence of a foreign device such as a catheter sharply
raises the level of interleukin-6, a protein that triggers a cascade of
responses within the immune system to repel the invader. That is what
happened in the volunteers who received a placebo.

But those who were injected with cocaine saw their interleukin-6 level rise
only one-third as much as the placebo subjects after four hours. Dr.
Halpern said that could have a big impact in fouling up the immune system.
"There's a delicate cascade of compounds that are released," he said. "You
want things to go in the normal order."

Dr. Halpern said the results help explain his own experience as a training
doctor in a drug-detoxification unit, when "almost every single person
coming in had a cold."

The study is one of a handful in the U.S. in which doctors injected human
volunteers, rather than rats, with cocaine. Dr. Halpern said Harvard's
ethics board and government regulators approved the study because the 30
volunteers had all used cocaine on their own between two and five times in
the previous month, though none were technically considered addicts.

In giving their go-ahead, regulators also considered the study's
significance in helping scientists understand how cocaine abuse damages the
body.

Dr. Halpern said more research is needed to show whether sniffed cocaine
has the same effect as the injected drug and whether the damage to the
immune system grows with repeated cocaine use.