Abstract Type : Oral presentation
Abstract Submission No.: A-0949
Abstract Topic : Glomerular and Tubulointerstitial Disorders
The Role of Urinary Complement Factor Ba as a Biomarker for Disease Activity and Prognostic Prediction in IgA Nephropathy
Seyoung Ryou1, Seung Yun Chae1, Do Hyun Na1, Sang Hun Eum1, Seok Joon Shin1, Hye Eun Yoon2
1Department of Internal Medicine-Nephrology, Incheon St. Mary's hospital, The Catholic University of Korea, Korea, Republic of
2Department of Internal Medicine-Nephrology, The Catholic University of Korea Seoul St. Mary's Hospital , Korea, Republic of
Objectives : Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerulonephritis, characterized by a broad spectrum of clinical and pathological features. As the complement system, particularly the alternative and lectin pathways, plays a central role in IgAN pathogenesis, numerous complement-targeting agents are under development and reliable biomarkers are increasingly needed.
Methods : We prospectively enrolled 49 patients with biopsy-confirmed IgAN with a minimum follow-up of one year and assessments at 6-month to 1-year intervals. Patients were stratified by urine protein-to-creatinine ratio (uPCR); high-proteinuria group, uPCR ≥1 g/g; low-proteinuria group, uPCR <1 g/g. Complement-related biomarkers will be quantified by enzyme-linked immunosorbent assay (ELISA), including urinary and serum Factor Ba and Bb (alternative pathway), urinary C4d and mannose-binding lectin (lectin pathway), and C5-9/membrane attack complex (terminal pathway). The primary outcome was a ≥40% decline in estimated glomerular filtration rate (eGFR). Associations between urinary Factor Ba and histopathological findings, and its prognostic value for renal outcomes, will be assessed using Cox regression analysis.
Results : The cohort comprised 17 patients (34.7%) in the low-proteinuria group and 32 (65.3%) in the high-proteinuria group. The two groups were largely comparable at baseline such as comorbidities, other laboratory parameters, and immunosuppressive therapy, but serum albumin was significantly higher in the low-proteinuria group (p=0.031). Over the follow-up period, seven patients (14.9%) reached the primary endpoint of ≥40% eGFR decline (high-proteinuria group 16.1% vs. low-proteinuria group 12.5%; p=1.000).
Conclusions : We have established a prospective IgAN cohort with detailed clinical, pathological, and follow-up data. With ELISA-based complement biomarker quantification ongoing, these findings provide the foundation for evaluating urinary Factor Ba as a prognostic biomarker and may inform the use of complement-targeted therapies in IgAN.
Methods : We prospectively enrolled 49 patients with biopsy-confirmed IgAN with a minimum follow-up of one year and assessments at 6-month to 1-year intervals. Patients were stratified by urine protein-to-creatinine ratio (uPCR); high-proteinuria group, uPCR ≥1 g/g; low-proteinuria group, uPCR <1 g/g. Complement-related biomarkers will be quantified by enzyme-linked immunosorbent assay (ELISA), including urinary and serum Factor Ba and Bb (alternative pathway), urinary C4d and mannose-binding lectin (lectin pathway), and C5-9/membrane attack complex (terminal pathway). The primary outcome was a ≥40% decline in estimated glomerular filtration rate (eGFR). Associations between urinary Factor Ba and histopathological findings, and its prognostic value for renal outcomes, will be assessed using Cox regression analysis.
Results : The cohort comprised 17 patients (34.7%) in the low-proteinuria group and 32 (65.3%) in the high-proteinuria group. The two groups were largely comparable at baseline such as comorbidities, other laboratory parameters, and immunosuppressive therapy, but serum albumin was significantly higher in the low-proteinuria group (p=0.031). Over the follow-up period, seven patients (14.9%) reached the primary endpoint of ≥40% eGFR decline (high-proteinuria group 16.1% vs. low-proteinuria group 12.5%; p=1.000).
Conclusions : We have established a prospective IgAN cohort with detailed clinical, pathological, and follow-up data. With ELISA-based complement biomarker quantification ongoing, these findings provide the foundation for evaluating urinary Factor Ba as a prognostic biomarker and may inform the use of complement-targeted therapies in IgAN.