C5 and hemolytic-uremic syndrome: In CM-HUS, treatment has been revolutionized by the introduction of eculizumab (Soliris®, Alexion Pharmaceuticals, Cheshire, CT, USA), a humanized monoclonal IgG antibody that binds to the C5 complement protein and blocks its cleavage [6], attenuating and preventing injury due to production of the terminal complement complex [7].