Abstract: SA-PO0881
Crescentic Glomerulonephritis with Pulmonary Haemorrhage in a Patient with High Titer Anti-Myeloperoxidase (MPO) Antibody and Triple-Positive Antiphospholipid Syndrome: Insights on a Rare Association
Session Information
- Glomerular Case Reports: ANCA, IgA, IgG, and More
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Laghrib, Sanae, CHU Brugmann, Brussels, Belgium
- Kamgang Semeu, Prochore N., CHU Brugmann, Brussels, Belgium
- Taghavi, Maxime, CHU Brugmann, Brussels, Belgium
- Jacobs, Lucas, CHU Brugmann, Brussels, Belgium
Introduction
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are small vessel inflammatory diseases. Antiphospholipid syndrome (APS) is an acquired thrombophilia characterized by thromboembolic events and /or obstetric manifestations. Kidneys are a major target organ in both diseases. The coexistence of APS and AAV is rare and raises questions about the overlapping immunopathogenic mechanisms.
Case Description
We present the case of a 42-year-old woman with triple positive thrombotic and obstetrical APS, and a history of 2 episodes of infectious interstitial pneumonia. She was admitted with dyspnoea, haemoptysis and epistaxis. Bronchoalveolar lavage confirmed intra-alveolar haemorrage. Laboratory workup revealed anaemia, thrombocytopenia, inflammatory syndrome and high anti MPO ANCA titer (1537 U/ml). Renal function revealed acute kidney injury AKIN 1 (Creatinine 1.17 mg/dL, eGFR 58 mL/min/1.73m2). Urinalysis revealed proteinuria (0.93 g/L; Albumin/creatinine: 520.9 mg/g creat), leukocyturia and haematuria. CT scan showed interstitial lung disease and renal biopsy showed fibrous crescents and secondary focal segmental glomerulosclerosis. The diagnosis of concomitant anti MPO AAV and triple positive APS was confirmed. Infectious and auto immune panels excluded differential diagnosis. She was treated with intravenous corticosteroids, and IV Cyclophosphamide, then maintenance treatment with Azathioprine and later Rituximab. APS was managed with vitamin K antagonists. The patient showed clinical and radiological improvements although ANCA titres remained high.
Discussion
APS and AAV share manifestations such as pauci-immune crescentic GN and pulmonary haemorrhage. It can be difficult to differentiate which disease causes clinical manifestations, thus managemement can be challenging. The coexistence of APS and AAV led us to reflect on the overlapping immunopathological pathways such as NETosis and complement activation, described in both diseases. These processes may contribute to a vicious cycle of sustained inflammation and progressive tissue damage. Additionally, the “two-hit” hypothesis in APS may apply to our patient, placing her at increased risk for thromboembolic events and potentially catastrophic antiphospholipid syndrome (CAPS).