AQP4 and paroxysmal nocturnal hemoglobinuria: In addition to AchR-Ab-positive gMG, eculizumab showed efficacy in paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and aquaporin-4 (AQP-4)-Ab-positive neuromyelitis optica spectrum disorder (NMOSD) [11,12,13].