The present study evaluating the effect of purified IgG from AQP4-antibody positive NMOSD patients on BBB properties showed that: 1) NMO-IgG induce an inflammatory secretome profile in brain microvessels, 2) have a direct impact on the molecular structure of the BBB and 3) induce a moderate functional alteration of the BBB. The gene discussed is AQP4; the disease is neuromyelitis optica.