C5aR is involved in the pathogenesis of kidney diseases including focal and segmental glomerulosclerosis [28,29], lupus nephritis [25,30], IgA nephropathy [31,32], c-ANCA vasculitis [33], p-ANCA (perinuclear anti-neutrophil cytoplasmic antibodies) vasculitis [34], ANCA-induced crescentic glomerulonephritis [35], C3 glomerulopathy [36], membranoproliferative glomerulonephritis [17], hemolytic uremic syndrome [37], and acute kidney injury [38]. Here, C5AR1 is linked to lupus nephritis.