C5 and paroxysmal nocturnal hemoglobinuria: The therapy with Eculizumab, which binds C5 and inhibits its activation, improved disease progression, survival, and quality of life in patients with aHUS and PNH but showed partial response only in some patients suffering from C3G, most likely due to the uncontrolled over-activation of the cascade in steps previous to Eculizumab’s point of action (Bomback et al., 2012).