Case 1: MOG titer reduced after TCZ, not RTXCase 2: Elevated erythrocyte sedimentation rate, a normal C-reactive protein, positive (1:640, speckled pattern), and a negative serum neuromyelitis optica/AQP4 IgG-antibodyCase 3: MOG-antibody seropositivity (titer 1:40). This evidence concerns the gene AQP4 and neuromyelitis optica.