Continued Eculizumab Therapy for Persistent Atypical Hemolytic Uremic Syndrome

Atypical hemolytic uremic syndrome (atypical HUS) is characterized by endothelial injury and microvascular thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia, and ischemic injury to organs, especially the kidney. Activation of complements is involved in the pathogenesis of atypical HUS. Eculizumab, a neutralizing monoclonal antibody directed against complement C5, has shown salutary effects in patients with atypical HUS. In this report, we present a 23-year-old man with atypical HUSwho was treated with eculizumab. During the first four weeks of treatment, eculizumab failed to achieve a remission. Microangiopathic hemolytic anemia and thrombocytopenia persisted, while renal function deteriorated necessitating initiation of hemodialysis. Continuation of eculizumab therapy, however, led to marked improvement in hemolytic anemia, thrombocytopenia, and renal function. After 10 weeks of eculizumab therapy, hemodialysis was discontinued. At 5-month follow-up, serum creatinine was 1.1 mg/dL with continued eculizumab therapy every other week. In addition, platelet count was normal, while there was no evidence of hemolysis. We conclude that in patients with persistent atypical HUS continued treatment with eculizumab can be helpful in achieving remission.