Outcome and risk of recurrence in a large cohort of idiopathic longitudinally extensive transverse myelitis without AQP4/MOG antibodies
on behalf of the OFSEP, SFSEP, and NOMADMUS study groups, Élisabeth Maillart, Françoise Durand‐Dubief, Céline Louapre, Bertrand Audoin, Bertrand Bourre, Nathalie Derache, Jonathan Ciron, Nicolas Collongues, de Sèze, Mikaël Cohen, Christine Lebrun‐Frénay, Nawel Hadhoum, Hélène Zéphir, Romain Deschamps, Clarisse Carra‐Dallière, Pierre Labauge, Philippe Kerschen, Alexis Montcuquet, Sandrine Wiertlewski, David Laplaud, Gwenaëlle Runavot, Sandra Vukusic, Caroline Papeix, Romain Marignier
Abstract
BACKGROUND: Longitudinally extensive transverse myelitis (LETM) is classically related to aquaporin (AQP4)-antibodies (Ab) neuromyelitis optica spectrum disorders (NMOSD) or more recently to myelin oligodendrocyte glycoprotein (MOG)-Ab associated disease. However, some patients remain negative for any diagnosis, despite a large work-up including AQP4-Ab and MOG-Ab. Data about natural history, disability outcome, and treatment are limited in this group of patients. We aimed to (1) describe clinical, biological, and radiological features of double seronegative LETM patients; (2) assess the clinical course and identify prognostic factors; and (3) assess the risk of recurrence, according to maintenance immunosuppressive therapy. METHODS: Retrospective evaluation of patients with a first episode of LETM, tested negative for AQP-Ab and MOG-Ab, from the French nationwide observatory study NOMADMUS. RESULTS: Fifty-three patients (median age 38 years (range 16-80)) with double seronegative LETM were included. Median nadir EDSS at onset was 6.0 (1-8.5), associated to a median EDSS at last follow-up of 4.0 (0-8). Recurrence was observed in 24.5% of patients in the 18 following months, with a median time to first relapse of 5.7 months. The risk of recurrence was lower in the group of patients treated early with an immunosuppressive drug (2/22, 9%), in comparison with untreated patients (10/31, 32%). CONCLUSIONS: A first episode of a double seronegative LETM is associated to a severe outcome and a high rate of relapse in the following 18 months, suggesting that an early immunosuppressive treatment may be beneficial in that condition.