Complement blockade in ANCA-associated vasculitis: an index case, current concepts and future perspectives.

Complement alternative pathway (cAP) hyperactivation seems to be involved in ANCA-associated vasculitis (AAV). We here describe a case of AAV with severe activation of cAP that developed acute renal failure. No mutation predisposing to cAP dysregulation was identified. We treated our patient with the standard immunosuppressive therapy, but disease progression was only reversed after the addition of eculizumab, a monoclonal antibody against C5; the patient eventually achieved an almost complete renal function recovery. A review of the available literature about the role of complement targeted therapies in the treatment of AAV is discussed.