We've known that cocaine use can increase someone's chances of getting HIV, mostly through needle sharing and other risky behaviors. Now a study further shows cocaine use fundamentally changes our immune cells, making them more susceptible to HIV infection.

Researchers used special mice engineered with a human immune system. They wanted to prove in a living organism their earlier findings which showed in petri dishes that the CD4 T cell becomes more vulnerable to HIV infection when exposed to cocaine. This is significant because CD4 T cells are a type of human immune cell that's normally resistant to HIV when it's not active. Would these resting T cells in the engineered mice be susceptible to HIV infection as they were in petri dish tests?

Using two groups of mice, researchers injected one group with cocaine and the other with a saline solution. After five days half the mice in each group were infected with HIV and continued to receive either cocaine or saline for two more weeks. Then researchers analyzed their blood and tissue.

The cocaine HIV infected mice had higher levels of the virus than the saline HIV mice. More significantly, about half the saline HIV mice had undetectable levels of infection while just a sixth of the cocaine HIV mice showed no infection.

They also found that cocaine use blunts the immune response which means certain T cells that normally would have been activated to rid the body of infection did not react. So just as the petri dish study predicted, cocaine use ups the chances of an HIV infection and influences the level of infection. This is one more reason to stay away from cocaine.