C5 and paroxysmal nocturnal hemoglobinuria: This antibody is known to bind to C5 at a crucial portion for its activation, and blocks the disassociation of C5 into C5a and C5b [10], and is clinically used to treat a variety of diseases associated with complement activation, such as atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria, myasthenia gravis, and optic neuromyelitis.