Assuming that the inflammatory environment induced by NMO-IgG has the capacity to alter the BBB, Claudin-5, Occludin, and ZO-1 protein expression analysis was performed in non-treated IBMs (n = 6) and in fresh IBMs treated with NMO-IgG1 (n = 6), and Control-IgG (n = 4), respectively, for 20 hours (Fig 3A). This evidence concerns the gene CLDN5 and neuromyelitis optica.