Abstract: PUB155
Complement Dysregulation Unmasked: Atypical Hemolytic Uremic Syndrome Emerging After Immunosuppressive Therapy in Rapidly Progressive IgAN
Session Information
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Chen, Ying, Center for Kidney Diseases, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Qiu, Yumei, Center for Kidney Diseases, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- Liu, Jin, Center for Kidney Diseases, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
- He, Weichun, Center for Kidney Diseases, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
Introduction
Rapidly progressive IgA nephropathy (RPIgAN) features extensive crescent formation, rapid renal function decline, and complement activation in its pathogenesis. Atypical hemolytic uremic syndrome (aHUS) is thrombotic microangiopathy (TMA) driven by uncontrolled activation of complement alternative pathway. Although both involve complement abnormalities, aHUS occurrence after improvement of RPIgAN with immunosuppressive (IS) therapy is rare.
Case Description
A 70-year-old female presented with rapidly progressive glomerulonephritis requiring dialysis. Renal biopsy confirmed IgAN, with 20/32 glomeruli showing global sclerosis and 9 of the remaining 12 showing crescents, diagnosing RPIgAN. No TMA signs were observed. She was treated with glucocorticoids and mycophenolate mofetil, resulting in improved renal function and dialysis discontinuation. However, subsequent laboratory tests revealed thrombocytopenia, microangiopathic hemolytic anemia, and a rebound in serum creatinine level, meeting diagnostic criteria for TMA. After excluding thrombotic thrombocytopenic purpura and Shiga toxin-associated HUS, a diagnosis of aHUS was considered and eculizumab was initiated. Thereafter, her hemolytic parameters gradually normalized, and renal function improved (Figure).
Discussion
This case suggests that patients with RPIgAN may harbor complement regulatory abnormality. Although IS therapy suppresses inflammation, it fails to control persistent complement activation. Subsequent aHUS development likely reflects ongoing complement-mediated endothelial injury that becomes clinically unmasked once inflammation is attenuated.
Cinical data and treatment methods of the patient.