The first successful eculizumab rescue therapy of a kidney transplant recipient with atypical hemolytic uremic syndrome in South Korea: a case report.

Atypical hemolytic uremic syndrome (aHUS) is a form of thrombotic microangiopathy (TMA) that can result in end-stage renal disease. Patients with aHUS often have predisposing dysfunction in the complement pathway, and continuous activation of complement proteins can be triggered after transplantation. Here, we report the first successful case of aHUS treatment in a kidney transplant recipient with early use of a C5 inhibitor, eculizumab, in South Korea. The patient was a 32-year-old man, and the donor was his 60-year-old mother. The graft showed immediate good function. On postoperative day (POD) 3, the clinical diagnosis of TMA was made. Persistent renal dysfunction despite 10 plasma exchange (PE) sessions prompted eculizumab treatment on POD 18 under suspicion of aHUS. Next-generation sequencing reported gene mutations classified as variants of unknown significance in coagulation-associated genes. The patient was discharged after three doses of eculizumab with serum creatinine of 1.82 mg/dL. In total, 16 doses of eculizumab were administered. At the last follow-up, 21 months after eculizumab discontinuation, the graft was well functioning. De novo TMA after kidney transplantation can be caused by sustained activation of the complement pathway, and early eculizumab treatment appears important in the successful treatment of aHUS refractory to PE.