Particularly, inhibitors of proteolysis are emerging as treatments for C1s in cold agglutinin disease (CAD, sutimlimab, Mullard, 2022; Broome, 2023), C3 (APL-2, compstatin, pegcetacoplan, Hillmen et al, 2021; Lamers et al, 2022; Mollnes et al, 2022), factor B and D for paroxysmal nocturnal hemoglobinuria (PNH, danicopan & iptacopan, Kang, 2024; Latour et al, 2024; Perkovic et al, 2025) or MASP-2 in thrombotic microangiopathy (TMA, narsoplimab, Elhadad et al, 2020). Here, C3 is linked to paroxysmal nocturnal hemoglobinuria.