Haemolytic uraemic syndrome.

Atypical haemolytic uraemic syndrome (aHUS) is a disease characterized by complement overactivation in which inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Identification of the underlying defect can both predict disease outcome and guide treatment. The ability to remove inhibitory autoantibodies and hyper-active complement components in addition to its ability to replace defective complement regulators means that plasma exchange is currently first-line therapy. In those with factor H and factor I mutations who do progress to end-stage renal failure, renal transplantation usually fails due to recurrent HUS. In this situation, combined liver-kidney transplantation has been suggested to correct the underlying genetic defect. Newer agents, such as the complement inhibitor eculizumab, may herald a new era in the treatment of aHUS.