This was followed by studies that showed treatment success using eculizumab, a humanized anti-C5 monoclonal antibody, in an SLE patient with concomitant refractory TMA (12, 13, 44–46) and in LN patients with evidence of complement overactivation on kidney by finding of C9 deposition (46). Here, C5 is linked to systemic lupus erythematosus.