De novo systemic atypical hemolytic uremic syndrome in an ABO-incompatible living kidney transplant recipient with a novel pathogenic CFHR1 gene mutation successfully treated with eculizumab: a case report

De novo systemic atypical hemolytic uremic syndrome (aHUS) post-kidney transplant is an uncommon entity associated with unfavorable outcome. We herein report a case of systemic and fulminant de novo aHUS accompanied by heart and respiratory failure in a 48-year-old male receiving ABO-incompatible living-related kidney transplant who was successfully treated with the anti-C5 monoclonal antibody eculizumab with complete recovery of allograft function. Genetic testing demonstrated a novel pathogenic heterozygous complement factor H-related 1 gene mutation in both the donor and the recipient. Our study highlights the high risks of post-transplant aHUS due to the complement gene mutations in both donor and recipient in living-related transplantation. Early intervention with eculizumab may be effective for reversing systemic aHUS in kidney transplant recipients.