Inclusion criteria:  Major patients who have received long-term treatment for NMO Patients with a prospectively diagnosed NMO using the 2015 NMO classification criteria (IPND) Patients who retrospectively meet the classification criteria of the 2015 NMO (IPND) Patients who have not expressed their opposition, after information, to the reuse of their data for research purposes.  Exclusion criteria:  Patient who expressed his opposition to participating in the study Lack of data on the assay of anti-AQP4 and anti-MOG antibodies Less than a year of taking a second-line treatment before the relay End of follow-up <1 year following the transfer, this therefore includes patients whose transfer took place less than one year before the date of data extraction