Abstract: SA-PO0957
Caveolin 1 Is a Reliable Biomarker of Endothelial Damage in the More Aggressive Subset of Antiphospholipid Syndrome Nephropathy
Session Information
- Pathology: Updates and Insights
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1800 Pathology and Lab Medicine
Authors
- Roccatello, Dario, Nephrology Dialysis, San Giovanni Bosco Hospital, University of Turin, Turin, Italy
- Fenoglio, Roberta, Nephrology Dialysis, San Giovanni Bosco Hospital, University of Turin, Turin, Italy
Background
Thrombotic microangiopathy (TMA) as seen in antiphospholipid syndrome nephropathy (APSN) is associated with poor renal outcomes, yet reliable biomarkers for its identification remain limited. Caveolin-1 (Cav-1) has emerged as a potential marker of endothelial damage and microvascular injury. This study investigates the diagnostic potential value of Cav-1 immunohistochemistry (IHC) in APSN-related TMA.
Methods
Patients were retrieved from the Piedmont and Aosta Valley Rare Disease Registry, from which a total of 771 APS cases had been recorded. Only case with biopsy-proven renal involvement were included. Cases were classified into three histopathological clusters: TMA (APSN-TMA), hyperplastic vasculopathy, and subendothelial oedema. Immunohistochemical staining for Cav-1 was performed and graded based on expression in peritubular and glomerular capillaries. Clinical and laboratory data, including antiphospholipid antibodies (aPL) profile, were correlated with Cav-1 expression
Results
Out of 771 patients with APS, a total of 11 patients with primary APS and renal involvement were retrieved (1,43%). APSN-TMA was identified in 7 (63.3%) cases, hyperplastic vasculopathy in 2 (18.1%), and subendothelial oedema in 2 (18.1%). Cav-1 expression was significantly higher in APSN-TMA cases in both glomerular (p=0.00091) and peritubular (p=0.047) compared to other clusters, with 5 of 7 APSN-TMA cases exhibiting diffuse (grade III) staining. Triple aPL postive testing was more prevalent in APSN-TMA cases, reinforcing their distinct pathophysiological profile.
Conclusion
APSN-TMA is a rare manifestation of a rare disease. Cav-1 is strongly associated with APSN-TMA and may serve as a novel marker for its diagnosis and stratification. Given the poor renal prognosis of APSN-TMA, identifying affected patients is crucial for optimizing management strategies. While these findings support Cav-1 as a promising diagnostic tool, further studies in larger cohorts are needed to validate its clinical utility and distinguish APSN-TMA from other forms of TMA. Future therapeutic implications, including eligibility for adjunctive immunomodulatory therapies, warrant further exploration.