Cocaine use can make otherwise resistant immune cells susceptible to HIV

In many ways, the spread of HIV has been fueled by substance abuse. Shared needles and drug users' high-risk sexual behaviors are just some of the ways that narcotics such as cocaine have played a key role in the AIDS epidemic in much of the world.

http://www.biologynews.net/archives/2013/10/02/cocaine_use_can_make_otherwise_resistant_immune_cells_susceptible_to_hiv.html