Abstract: Ｏｂｊｅｃｔｉｖｅ：To analyse efficacy of short-term use of complement C5 inhibitor eculizumab, and adverse reactions in patients with atypical haemolytic uremic syndrome (aHUS).
Ｍｅｔｈｏｄｏｌｏｇｙ：Five patients with aHUS who were regularly treated in Sichuan Provincial Peoples Hospital between January 2023 and May 2024 were retrospectively collected and analysed for clinical manifestations, laboratory examinations, renal pathological examinations, genetic test results, the therapeutic efficacy of eculizumab and the adverse reactions.
Ｒｅｓｕｌｔｓ：One of the five patients with aHUS was male, with a median age of 40 (17～66) years, etiologu included renal transplantation, malignant hypertension, autoimmune disease, and primary aHUS. All presented clinically with acute renal failure, proteinuria, haematuria, anaemia and thrombocytopenia,dicrease of complement C3. Renal biopsy was performed in 3 cases and showed endothelial cell damage and microthrombosis. 3 cases received dialysis, 3 cases had renal biopsies, all 4 patients were treated with steroids (2 received methylprednisolone pulse therapy), 1 kidney transplant-related case was treated with rabbit anti-human thymus immunoglobulin (ATG), intravenous gammaglobulin, and 1 with CD20 monoclonal antibody (with systemic lupus erythematosus in the primary disease). The median time from diagnosis of aHUS to treatment with eculizumab was 20 (2～37.5) days, with 4～20 times of eculizumab, and a mean of 7(4.5～8.5)days post-treatment all patients achieved haematological remission, 3 patients achieved nephrological remission, and 1 patient was taken off dialysis. At 8~24 weeks months of follow-up creatinine and LDH were significantly lower and eGFR, haemoglobin and platelets were significantly higher than before treatment (P<0.001). No significant adverse reactions were found.
Ｃｏｎｃｌｕｓｉｏｎ：aHUS has diverse clinical manifestations, rapid progression, and poor prognosis, and eculizumab is the first-line treatment option for aHUS. Once diagnosed, treatment can be initiated immediately, which can rapidly improve the haematological indexes and renal function, and the long-term clinical benefits still need to be further studied.

Key words: atypical hemolytic uremic syndrome, eculizumab, adverse reactions