Abstract: SA-PO0842
Clinicopathologic Features and Kidney Outcomes in Primary Antiphospholipid Syndrome-Associated Nephropathy
Session Information
- Glomerular Diseases: Management, Evolving Strategies, and Practice-Changing Advances
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Bercaru, Irina Lucia, Institutul Clinic Fundeni, Bucharest, Romania
- Iercosan, Alexandru Radu, Institutul Clinic Fundeni, Bucharest, Romania
- Lujinschi, Stefan Nicolaie, Institutul Clinic Fundeni, Bucharest, Romania
- Ismail, Gener, Institutul Clinic Fundeni, Bucharest, Romania
Background
Antiphospholipid syndrome (APS)-associated nephropathy is an underrecognized manifestation of primary APS, characterized by heterogeneous vascular and glomerular lesions. Longitudinal clinicopathologic data remains limited.
Methods
We retrospectively analyzed patients with primary APS-associated renal involvement fulfilling the 2023 ACR/EULAR APS classification criteria. Clinical, imaging, histopathologic, treatment, and longitudinal data were collected. Renal phenotypes were classified as macrovascular, microvascular or mixed using predefined clinicopathologic criteria.
Results
Eleven patients were included (median age at renal onset: 50 years [IQR 35–60]; 27.3% females). 27.3% had triple antiphospholipid antibody positivity. At presentation, 90.9% had hypertension, 36.4% nephrotic syndrome, and 18.2% acute kidney injury. Renal phenotypes were predominantly microvascular (63.6%), while 27.3% had macrovascular involvement including renal infarction, renal asymmetry, and renal artery stenosis. Kidney biopsy was performed in 63.6% and showed APS nephropathy features in all cases, with chronic thrombotic microangiopathy patterns in 6/7 (85.7%), chronic ischemic glomerulopathy in 4/7 (57.1%), diffuse endotheliosis in 3/7 (42.9%), and diffuse podocyte foot process effacement in 3/7 (42.9%). Electron-dense deposits were absent in all biopsies assessed by electron microscopy. Rituximab-based regimens were used in 63.6% of cases, while complement inhibition was reserved for severe or refractory disease in 18.2%. One patient required kidney replacement therapy (KRT) at presentation with transient renal recovery after multimodal therapy including plasma exchange, followed by progressive kidney decline, while another progressed and required KRT during follow-up. After a median follow-up of 20 months (IQR 9–25), 72.7% achieved partial renal response, 63.6% showed renal function stabilization, and blood pressure control was achieved in 81.8%. No deaths or renal relapses occurred.
Conclusion
Primary APS-associated nephropathy is predominantly characterized by chronic microvascular and endothelial injury patterns with frequent chronic TMA-related lesions. Despite heterogeneous presentations, most patients achieved renal stabilization under multimodal therapy, although persistent chronic kidney disease burden remained substantial.