C5AR1 and anti-neutrophil cytoplasmic antibody-associated vasculitis: A powerful antagonist of C5aR1, Avacopan, has been approved by the FDA for the additional treatment of severe active cytoplasmic antibody antineutrophil (ANCA)-associated vasculitis (AAV) in combination with standard therapy in adults; it significantly improves patient kidney function by reducing proteinuria and increasing the estimated glomerular filtration rate [103].