AQP4 and neuromyelitis optica: Nasello et al. report titres of antibodies against acquaporin-4 (AQP4-IgG) and myelin oligodendrocyte glycoprotein (MOG-IgG) increase in 40% of Neuromyelitis Optica Spectrum Disorder and MOG-IgG-associated disease relapses, remaining stable 2–4 years post-attacks.