AQP4-IgG antibodies were absent in two patients with NMO (4%), 21 patients with HR-NMO (40%), 31 CIS patients (97%) and all patients with ADEM and MS as well as all controls (CTRL) including patients with systemic lupus erythematosus (SLE), other neurological diseases (OND) and healthy individuals (Table 1). Here, AQP4 is linked to neuromyelitis optica.