Although previous studies have indicated that the BBB remains intact and functionally unchanged in patients with MG [66, 67], our findings in Fig. 4 demonstrate a downregulation of Claudin5 (Cldn5), CXC43 (Gja1) and CD31 (Pecam1) expression in cerebral microvascular ECs of EAMG rats as assessed by western blot and qPCR. This evidence concerns the gene CLDN5 and myasthenia gravis.