Atypical hemolytic uremic syndrome: from the rediscovery of complement to targeted therapy.

Atypical hemolytic uremic syndrome (aHUS) is a devastating form of renal thrombotic microangiopathy. In the last five years, we have finally witnessed a dramatic improvement in the management of aHUS patients, and three breakthroughs in our understanding of aHUS have led to such an improvement. The first breakthrough was the emergence of a new clinical picture of aHUS (frequency of adult cases, and overall poor renal prognosis despite plasma therapy). The second breakthrough was the identification of complement alternative pathway dysregulation as a major risk factor for aHUS. The third breakthrough was the availability in clinical practice of the first complement inhibitor, the anti-C5 monoclonal antibody, eculizumab. Available data from case series and prospective studies indicate that eculizumab use has dramatically improved the renal prognosis of aHUS. These breakthroughs have prompted the French working group on aHUS to propose a new algorithm for the management of aHUS in children and in adults. This algorithm will evolve as we gain new insights in the pathogenesis and evolution of aHUS in the eculizumab era.

Fakhouri F ，Frémeaux-Bacchi V ，Loirat C 《-》

Insights from the use in clinical practice of eculizumab in adult patients with atypical hemolytic uremic syndrome affecting the native kidneys: an analysis of 19 cases.

Atypical hemolytic uremic syndrome (aHUS) is a devastating form of renal thrombotic microangiopathy. Despite plasma exchange, the standard treatment of aHUS for decades, the renal prognosis for patients with aHUS has remained poor. We assessed the off-trial use of eculizumab in adult patients with aHUS affecting the native kidneys. A retrospective study was conducted. aHUS was defined as the presence of 3 or more of the following: acute kidney injury (serum creatinine >1.4 mg/dL [120 μmol/L]), mechanical hemolytic anemia, thrombocytopenia, and the presence of thrombotic microangiopathy features in a kidney biopsy specimen. Patients who had received 4 or more weekly 900-mg infusions of eculizumab were included. 19 patients were identified through a query sent to all French nephrology centers. Evolution of kidney function, hemolysis, and thrombocytopenia after the initiation of eculizumab therapy. All patients had acute kidney injury (serum creatinine range, 2.2-17.0 mg/dL) and 12 required hemodialysis. Thirteen patients carried a mutation in 1 complement gene and 1 had anti-factor H antibodies. For first-line therapy, 16 patients underwent plasma exchange and 3 patients received eculizumab. Median time between aHUS onset and eculizumab therapy initiation was 6 (range, 1-60) days and median time to platelet count normalization after eculizumab therapy initiation was 6 (range, 2-42) days. At the 3-month follow-up, 4 patients still required dialysis, 8 had non-dialysis-dependent chronic kidney disease, and 7 had normalized kidney function. At last follow-up (range, 4-22 months), 3 patients remained dialysis dependent, 7 had non-dialysis-dependent chronic kidney disease (estimated glomerular filtration rate, 17-55 mL/min/1.73 m(2)), and 9 had normal kidney function. Risks of reaching end-stage renal disease within 3 months and 1 year of aHUS onset were reduced by half in eculizumab-treated patients compared with recent historical controls. Retrospective study and use of historical controls. Our data indicate that eculizumab improves kidney disease outcome in patients with aHUS.

Fakhouri F ，Delmas Y ，Provot F ，Barbet C ，Karras A ，Makdassi R ，Courivaud C ，Rifard K ，Servais A ，Allard C ，Besson V ，Cousin M ，Châtelet V ，Goujon JM ，Coindre JP ，Laurent G ，Loirat C ，Frémeaux-Bacchi V ... -  《-》

Eculizumab in anti-factor h antibodies associated with atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (aHUS) is a life-threatening multisystemic condition often leading to end-stage renal failure. It results from an increased activation of the alternative pathway of the complement system due to mutations of genes coding for inhibitors of this pathway or from autoantibodies directed against them. Eculizumab is a monoclonal antibody directed against complement component C5 and inhibiting the activation of the effector limb of the complement system. Its efficacy has already been demonstrated in aHUS. The present article reports for the first time the use of eculizumab in a patient presenting with aHUS associated with circulating anti-complement Factor H autoantibodies and complicated by cardiac and neurologic symptoms. Our observation highlights the efficacy of eculizumab in this form of aHUS not only on renal symptoms but also on the extrarenal symptoms. It also suggests that eculizumab should be used very promptly after aHUS presentation to prevent life-threatening complications and to reduce the risk of chronic disabilities. To obtain a complete inhibition of the effector limb activation, the advised dosage must be respected. After this initial therapy in the autoimmune aHUS form, a long-term immunosuppressive treatment should be considered, to prevent relapses by reducing anti-complement Factor H autoantibody plasma levels.

Diamante Chiodini B ，Davin JC ，Corazza F ，Khaldi K ，Dahan K ，Ismaili K ，Adams B ... -  《-》

Eculizumab as first-line therapy for atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (aHUS) is a genetic, life-threatening, chronic disease that can affect patients of all ages. aHUS is caused by uncontrolled complement activation due to genetic defects of complement regulation. Plasma exchange or infusion has been used to manage aHUS and may transiently maintain hematologic variables in some patients, but as the underlying complement dysregulation persists, end-stage renal disease or death occurs in 33% to 40% of patients during the first clinical manifestation. Here we present a pediatric case showing that first-line eculizumab treatment successfully blocked the progression of thrombotic microangiopathy in aHUS.

Christmann M ，Hansen M ，Bergmann C ，Schwabe D ，Brand J ，Schneider W ... -  《-》

A new era in the diagnosis and treatment of atypical haemolytic uraemic syndrome.

Westra D ，Wetzels JF ，Volokhina EB ，van den Heuvel LP ，van de Kar NC ... -  《-》