Abstract: TH-PO0506
Circulating Secretory IgA is a Potent Prognostic Biomarker of IgAN
Session Information
- Glomerular Diseases: Clinical, Outcomes, and Therapeutics Research - IgAN
October 22, 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
- Arbez, Laure, GIMAP INSERM U1111 CIRI, Saint Etienne, France
- Mariat, Christopher R., CHU Saint Etienne, Saint Etienne, France
- Paul, Stéphane, CHU Saint Etienne, Saint Etienne, France
- Maillard, Nicolas, CHU Saint Etienne, Saint Etienne, France
Background
IgA Nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide, leading to frequent progression to kidney failure. An increase of circulating Gal-deficient IgA1 (gd-IgA1) in serum is a hallmarkof this disease, but this biomarker displays poor diagnostic and prognostic performances. Some recent data strongly suggest the role of secretory IgA (SIgA) as a key driver of IgAN pathogeny. Herein, our objectives were (1) to design a highly specific assay to measure SIgA1 in serum based on affinity to secretory component (SC) (2) to establish diagnostic and (3) prognostic performances of this potential biomarker in IgA nephropathy
Methods
We first designed a highly specific, cross-capture ELISA IgA-secretory component. Then, the diagnostic study compared serum concentrations of SIgA for 312 biopsies proven IgAN patients in CHU Saint Etienne, to 121 healthy blood donors (HD), and then, prognostic performances were evaluated. Serum concentrations were compared between IgAN patients and HD, and then correlations were evaluated between SIgA and proteinuria, eGFR, blood pressure, histopathological scores (MEST-C score). Prognosis was given as cox models to predict kidney failure.
Results
The ELISA was technically validated with a strong signal against purified secretory component, a reactivity against human colostrum, and no cross-reaction against native IgA1. Concentration of circulating SIgA was significantly higher in IgAN patient’s vs HD (p=0.0007).This marker also showed strong correlation with severity of the disease at diagnosis, marked by proteinuria (p<0.0001), eGFR (p<0.0001), mean blood pressure (p=0.0005) and histological scores as Oxford S1 (p=0.039) and T1 (p=0.01). Univariate cox analysis showed better survival without kidney failure for patients with lower value of SIgA1 compared to their high value counterparts (HR=1.16, p<0.00001). This prognostic impact was robust after multivariate adjustment on proteinuria (p<0.0001) and IgAN-PT global linear predictor (p=0.01).
Conclusion
Secretory IgA concentration at diagnosis, given by a highly SC-specific assay, can provide fair diagnostic performances and high prognostic biomarker performances, including prediction of renal survival after adjustment on IgAN-Prediction Tool. these results strongly suggest a major role of transcytosed circulating IgA on the progression of the disease, and provides a potential useful tool for disease monitoring.