Immunology 2Saturday, October 13, 2007, 15:30 - 17:00
NMO-IgG predicts the outcome of recurrent optic neuritisM. Matiello, A. Jacob, S. Pittock, V. Lennon, C. Lucchinetti, D. Wingerchuk, B. Weinshenker (Rochester, USA)
Objective: To investigate whether NMO-IgG seropositivity is associated with demographic and clinical features and predicts outcome in patients with recurrent optic neuritis (RON).
Background: RON may herald either multiple sclerosis (MS) or neuromyelitis optica (NMO) or it may occur repeatedly without other neurological manifestations. The treatment and prognosis for RON is anticipated to differ in these contexts. The aquaporin 4-specific serum autoantibody, NMO-IgG, is a highly specific biomarker for NMO but its value for patients with RON has not been addressed.
Design/Methods: Patients were ascertained through a clinical biospecimens database (2000-2007) comprising individuals tested for NMO-IgG for a multitude of neurological conditions including NMO, RON, longitudinally-extensive transverse myelitis and MS. Only patients with RON who did not satisfy criteria for MS or NMO were included in this study. We compared the demographic and clinical features and the subsequent clinical course of NMO–IgG seropositive patients and NMO-IgG seronegative patients.
Results: Thirty-four patients were included: 20 seronegative and 14 seropositive. Among 25 consecutive patients with RON seen at Mayo Clinic, 5 (20%) were seropositive. Five of 12 (41.7%) of the seropositive patients versus 2 of 19 (10.5%) seronegative patients had non-Caucasian ancestry (p=0.07). All 14 NMO-IgG seropositive patients, versus 11 of 17 (64.7%) seronegtive patients, had at least one attack in which the visual acuity was worse than 20/200 in the affected eye (p=0.05). After a median followup of 8.4 years, 6 of 12 (50%) seropositive patients experienced an episode of transverse myelitis (TM) and fulfilled diagnostic criteria for NMO and 1 of 15 (6.7%) seronegative patients experienced an episode of TM fulfilling McDonald criteria for MS (p=0.03). Among the sepopositive patients, the NMO-IgG titer was higher on those who developed myelitis, 5 of 7 (71,4%) that had a titer greater than 1:480 and only 1 of 5 (20%) in the group with a titer equal or lesser than 1:480 had an episode of TM (p=0.07).
Conclusion/Relevance: Seropositivity for NMO-IgG of patients with RON is associated with clinical differences at diagnosis and in follow-up. NMO-IgG seropositive RON represents a limited or inaugural form of NMO, thus we recommend that treatment effective for NMO should be instituted for such patients.