A British study is testing the HIV antiretroviral (ARV) Isentress (raltegravir) as a possible treatment for the brain lesions of multiple sclerosis, MedPage Today reports. The study pursues a controversial theory that MS may be caused by what are known as human endogenous retroviruses. HERVs are comprised of the remnants of retroviruses that infected the human race in the highly distant past and then became woven into the human genome’s “germline.”

Past research has found that people living with HIV are apparently much less likely to develop MS. For a study reported in the fall of 2013, investigators analyzed the U.K. general practice database, which provided medical information on about 55 million people. They narrowed their investigation to 21,000 HIV-positive Britons and 6.7 matched controls and then followed them for an average of seven years. Those living with HIV had a 62 percent reduced risk of MS. If considering only MS diagnoses made more than a year after the HIV diagnosis, the reduction in risk increased to 78 percent.

To read the MedPage Today story, click here.