http://www.wheelchairkamikaze.com/2013/05/can-anti-hiv-drugs-stop-ms.html

talks of the HIV drug trial.

http://www.biomedcentral.com/1471-2377/13/111/

talks of the research of the specific retrovirus  HERV-FC1 for RRMS, SPMS and mentions HERV-FC16 for PPMS