Recent research suggests that antiretrovirals (ARV) to treat HIV may also fight multiple sclerosis. A study of people hospitalized in England between 1999 and 2011, including 21,000 people living with HIV who were compared with a control group of nearly 5.3 million HIV-negative people, found that the HIV-positive group was 62 percent less likely to develop MS. The more time that passed following an HIV diagnosis, the greater this apparent relative reduction in risk: By five years the figure hit 85 percent.

Julian Gold, MD, the director of The Albion Centre in the Prince of Wales Hospital in Sydney, Australia, and the study’s lead author, says that there is no way to know for sure from his findings whether ARVs can in fact treat MS. After all, this was an observational study and not the gold standard of clinical research, a randomized controlled trial. But he’s in the process of conducting a small study to begin the long and challenging process necessary to prove the connection, should it exist.

“I’m particularly interested in seeing whether we can use [ARVs] for other serious autoimmune conditions, like rheumatoid arthritis, lupus, type 1 diabetes, and other neurological conditions for which the treatments at the moment are terrible,” Gold says.