Creation of a French cohort of Devic’s neuromyelitis optica and related neurological disorders
Devic’s neuromyelitis optica (DNMO)
Devic’s neuromyelitis optica (DNMO) is a demyelinating and inflammatory disease of the central nervous system (CNS) essentially restricted to the spinal cord and the optic nerves. It is a rare disorder. Prevalence is unknown in Western countries. Epidemiological data are poor and based only upon few retrospective and small-sized studies. Moreover, those works did not incorporate cases defined by the recently described specific auto-antibody for the disease, NMO-IgG, and therefore did not consider the new spectrum of DNMO.
Since the first description by Eugène Devic and Fernand Gault in 1894, the relationship between DNMO and multiple sclerosis (MS) has been controversial. Recent clinical, epidemiological, pathological and immunological data suggest that MS and DNMO are distinct entities. DNMO is now considered to be an auto-immune, antibody-mediated disease especially since the identification by the Mayo Clinic of a specific serum autoantibody, NMO-IgG. This antibody was initially proposed to differentiate DNMO and MS. Furthermore, NMO-IgG have enlarged the clinical spectrum of DNMO and could also be helpful to predict relapses or conversion to DNMO after a first episode of longitudinally extensive transverse myelitis or isolated optic neuritis.
This distinction between DNMO and MS is however crucial, as prognosis and treatment are indeed different. Early immunosuppressive treatments are used for relapse prevention in DNMO by contrast to standard MS immunomodulatory drugs (beta-interferon, glatiramer acetate) which are usually inefficient or deleterious. Clinical practice is however very heterogeneous regarding treatment choice and duration. For this reason, a prospective follow-up study in well characterized patients is needed.
Our first objective is the creation of a French cohort of patients suffering from definite DNMO and related neurological syndromes, defined as recurrent or simultaneous optic neuritis, idiopathic single or recurrent longitudinally extensive transverse myelitis (spinal cord lesion seen on MRI >3 vertebral segments). The aim is to describe the clinical, radiological and biological features of these patients and their clinical course with and without specific treatments. Through the samples received in our laboratory for NMO-IgG detection and the previous work of Pr Jérôme De Sèze and Dr Nicolas Collongues, we have already established a cohort of 128 patients with definite DNMO, 20 with longitudinally extensive transverse myelitis and 15 with isolated optic neuritis seropositive for NMO-IgG.
Our second objective is the creation of a specific collection of blood, sera, cerebrospinal fluid and tissue, for DNMO and related disorders in the biological resource centre, Neurobiotec (Hôpital Neurologique, Hospices Civils de Lyon). The aim of this biobank is to improve NMO-IgG detection methods and to be used for more fundamental studies.
This creation of a French cohort of patients suffering from definite DNMO and related neurological syndromes is made possible by existing tools (the EDMUS software recently adapted to DNMO specificities; Neurobiotec) organisations (EDMUS users network, regional networks around MS patient care) and teams (INSERM unit U842 of Pr Jérôme Honnorat; Department of Neuro-epidemiology and Pharmaco-epidemiology in Lyon) that are all guaranties of its feasibility.