Multiple sclerosis-associated retrovirus and optic neuritis

One prognostic factor for early multiple sclerosis (MS) patients to develop a definite MS may be the presence of the MS-associated retrovirus (MSRV) in the cerebrospinal fluid (CSF). We designed a specific study on a cohort of optic neuritis (ON) patients to evaluate the MSRV-dependent conversion to MS relative to the prediction conferred by magnetic resonance imaging (MRI) and CSF abnormalities. At follow-up, 33.3% MSRV+ and 0% MSRV- ON patients developed MS (P = 0.03). The prediction value is lower than that given by CSF and MRI abnormalities (42.3%). This intriguing finding is discussed in the light of the abundant discrepancies observed in the MSRV literature.