Cocaine and Intensity of H.I.V. Are Related in a Study of Mice
…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."
http://www.nytimes.com/2002/02/15/health/15IMMU.html?todaysheadlines&pagewanted=all