The anti-human C5/C5a antibody MEDI7814 neutralizes the C5aR1 and C5aR2 receptors (Colley et al, 2018); a C5aR antagonist, Avacopan (CCX168), was approved in 2022 for use in ANCA vasculitis (Jayne et al, 2021). Here, C5 is linked to vasculitis.