C5AR1 and systemic lupus erythematosus: With regards to SLE, although experimental C5 inhibition has long been known to ameliorate the (NZBxNZW)F1 experimental model (Wang et al., 1996), and as shown above the C5a product of C5 activation promotes renal injury (Wenderfer et al., 2005), the role of the MAC itself beyond C5a does not appear to have been studied in either patients or published models through inhibitory approaches (Fig. 1F).