Brief Review and a Clinical Case of Hemolytic Uremic Syndrome Associated with Interferon β Treatment

The hemolytic uremic syndrome (HUS) is one of the thrombotic microangiopathies and it consists of the triad of nonimmune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The atypical form of HUS (aHUS) is related to causative mutations in complement genes. Some conditions act as a trigger for aHUS in individuals that have a genetic background predisposing to complement activation. Interferon β is a recombinant-protein therapy approved to treat multiple sclerosis (MS), and can be a causative agent in the occurrence of HUS through anti-angiogenic activity. In this paper, we briefly review aHUS clinical and genetic characteristics. Furthermore, we present a case of a 48-year-old woman, diagnosed with MS and treated with INFβ-1b from 2008. In December 2015, she presented with asthenia and loss of muscular strength in the legs and she quickly developed aHUS. Our case suggests that INFβ is a possible triggering factor for HUS.