The clinical characteristics of AQP4 antibody positive NMO/SD in a large cohort of Chinese Han patients.

We aim to summarize the clinical features of AQP4-ab-positive NMO/SD in a large Chinese Han cohort. The clinical data of 145 AQP4-ab-seropositive patients was retrospectively reviewed. 55.9% (81/145) of the patients were defined as NMO while 39.3% (57/145) were defined as NMOSD according to the criteria established in 2006 and 2007. The mean onset age was 34.4years and the female to male ratio was 8.7:1. The median disease duration was 57months. The median of "time to second attack" and "time to develop NMO" was 7 and 13months respectively. Ratio of monophasic to relapsing was 1:7.1. Myelitis and optic neuritis (ON) were the most common manifestations at onset, followed by postrema syndrome. The median age of patients presenting with ON at disease onset was significantly younger than patients presenting with myelitis. Only 17.2% of the patients younger than 30years presented with longitudinally extensive transverse myelitis (LETM) at onset, while 55.6% of the patients over 30years presented with LETM at onset. The patients presenting with ON at disease onset all exhibited a relapsing course, had a higher probability of subsequent involvement of other CNS regions and developing into definite NMO over time compared with those with LETM as the first attack. AQP4-ab levels were higher in patients with circulating auto-antibodies such as ANA, SSA, anti-Ro-52, anti-dsDNA, anti-histone antibody, pANCA and SSB, and positively correlated with CSF protein concentrations.