Aquaporin-4 Serostatus and Visual Outcomes in Clinically Isolated Acute Optic Neuritis.

BACKGROUND: Aquaporin-4 antibodies (AQP4-Ab) are associated with neuromyelitis optica spectrum disorder (NMOSD) and typically this disorder has a poor visual prognosis as a result of optic neuritis (ON). Our aim was to report the clinical features at onset and final visual outcomes at 6 months of patients with ON who were positive for AQP4-Ab vs. those who were negative for AQP4-Ab. METHODS: Retrospective cohort study. AQP4-Ab were tested by indirect immunofluorescence in 57 patients with a first episode of ON. All patients initially were referred for consideration of multiple sclerosis ON (MSON), NMOSD, or any other inflammatory central nervous system disorder during follow-up (41.31 ± 24.32 months). Our patients were diagnosed as having NMOSD, MSON, chronic relapsing inflammatory ON, and single isolated ON. Risk factors associated with visual outcomes of ON patients were assessed through an ordinal regression model. RESULTS: Positive AQP4-Ab were associated with male sex (P = 0.02), earlier age of onset (P = 0.01), and myelitis relapses (P = 0.04). Seronegative group had fewer recurrences of ON than the seropositive group (35% vs 58%, P = 0.14). Patients that were positive for AQP4-Ab did not have worse visual acuity at baseline and after 6 months. However, poor visual acuity during first attack was associated with a worse visual acuity at 6 months (odds ratio = 2.28, 95% CI [1.58-3.28], P = 0.03). CONCLUSIONS: At 6 months, positive AQP4-Ab vs negative AQP4-Ab patients no evidence of poorer visual acuity. Lower visual acuity at baseline was associated with poor visual recovery at 6 months.

Diagnostic Utility of Systematic Aquaporin-4 Antibodies Determination in the First Event of Immune-Mediated Optic Neuritis.

BACKGROUND: Antibodies against aquaporin-4 (AQP4-ab) have diagnostic and prognostic value. However, little is known to date about their utility in the first event of optic neuritis (ON). OBJECTIVE: To evaluate the utility of systematic AQP4-ab determination in a retrospective cohort of patients with a first onset of ON. PATIENTS AND METHODS: All patients (n = 42) were tested for AQP4-ab in the following context: typical ON (TON) and atypical ON (AON). Clinical, radiological and biochemical data were collected; patients with TON vs. AON and AQP4-ab positive vs. negative were compared. RESULTS: The proportion of AQP4-ab seropositive patients was 40% in the TON group vs. 40.9% in the AON group. Visual acuity (VA) at baseline was poor in AON patients (p = 0.02) and these patients were associated with worse VA outcome (p < 0.001) at 6 months compared with TON patients, with a median follow-up of 3.27 ± 1.79 years. Brain MRI with dissemination in space criteria (p < 0.001), spinal cord partial lesions (p < 0.001) and oligoclonal bands (p = 0.02) were associated with the initial stages of TON. VA severity, number of myelitis attacks and ON relapses did not differ significantly between seropositive and seronegative patients. AQP4-ab were detected only in neuromyelitis optica spectrum disorders patients. CONCLUSION: This study showed a high seropositivity for AQP4-ab in TON patients, suggesting that it could diagnostic utility at the onset of ON.