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Background: Neuromyelitis optica (NMO) is an aggressive devastating autoimmune disorder affecting predominantly optic nerves and the spinal cord. We are able to assess the serum antibodies against aquaporin 4 (anti-AQP4 Ab, also known as NMO-IgG), which are highly sensitive and specific for NMO. These antibodies can significantly facilitate establishment of correct diagnosis already in the time of first symptoms, and, in case of isolated ON or longitudinally extensive myelitis, they can predict the risk of relapse or full manifestation of NMO. These antibodies are believed to play a role in the pathogenesis of this disease. Methods: We studied anti-AQP4 Ab titers in sera of 16 patients (disease duration from 1 to 563 months). Eight of them fulfilled the revised Wingerchuk’s criteria. Four of them were treated for optic neuritis and anti-AQP4 Ab were detected in these patients. All of these patients were divided into two groups: Group I (n=8) had one or more relapses during the last 12 months of the disease course. The serum samples were tested every third month and during the relapse (number of samples was 47). Group II (n=8) had no relapse during the last 12 months; the serum samples were tested every third month (number of samples was 16). Furthermore, we compared the Ab titers pooled from both groups, according to the disease status at the time, when the sample was obtained – at time of remission (number of samples was 45) compared to the time of relapse (number of samples was 17). Anti-AQP4 Ab have been tested by indirect immunofluorescence on AQP-4 transfected HEK cells. The anti-AQP4 Ab titers were 1:10, 1:32, 1:100, 1:320, 1:1000, 1:3200. Statistical comparisons were conducted using non-parametric methods (Mann-Whitney test). Results: Significantly higher anti-AQP4 Ab titres were found in relapsing group I (median 1:320) in comparison to non-relapsing group II (median 1:100, p=0,00015). Significantly higher anti-AQP4 Ab titres were also detected during relapse (1:1000) in comparison to the time of remission (median 1:320, p=0,011). Conclusion: The titers of anti-AQP4 Ab may prove as a useful tool for monitoring of the disease activity in patients with definite diagnosis of NMO or a “high risk” for NMO.

Read More: The assessment of anti-AQP4 antibody titre as a possible marker of disesase activity in patients with neuromyelitis optica