Anti–JC virus antibody levels in serum or plasma further define risk of natalizumab‐associated progressive multifocal leukoencephalopathy

Abstract

Anti-JCV antibody levels in serum/plasma, measured as index, may differentiate PML risk in anti-JCV antibody-positive MS patients with no prior immunosuppressant use. Continued evaluation of anti-JCV antibody index and PML risk is warranted.