Lipid-specific immunoglobulin M bands in cerebrospinal fluid are associated with a reduced risk of developing progressive multifocal leukoencephalopathy during treatment with natalizumab. - Villar LM; Costa-Frossard L; Masterman T; Fernandez O; Montalban X; Casanova B; Izquierdo G; Coret F; Tumani H; Saiz A; Arroyo R; Fink K; et al. (Annals of neurology, 2015)