Anti-Factor H Autoantibody-Associated Hemolytic Uremic Syndrome: Review of Literature of the Autoimmune Form of HUS

Non-Shiga toxin-associated hemolytic uremic syndrome (atypical HUS) is a rare form of thrombotic microangiopathy that associates hemolytic anemia, thrombocytopenia, and acute renal failure. The disease has been demonstrated to be linked with a complement alternative pathway dysregulation due to genetic defects but also to development of autoantibodies to factor H (FH), the main plasmatic alternative pathway regulatory protein. In this review, we summarize the more recent data of this autoimmune form of HUS at the level of epidemiology and its clinical and biological features. We propose the performance of anti-FH autoantibodies screening at the very onset of the disease in all cases of HUS to first make the proper diagnosis as early as possible, and second to support an appropriate therapy including early plasma exchanges and immunosuppressive treatments.