Abstract: SA-PO0827
Glomerular CR1 Expression Is Associated with Disease Severity and, When Combined with C4b Deposition, Improves Risk Stratification in IgAN
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
- Zhang, Hanzhen, Huashan Hospital Fudan University, Shanghai, China
- Liu, Shaojun, Huashan Hospital Fudan University, Shanghai, China
- Xie, Qionghong, Huashan Hospital Fudan University, Shanghai, China
- Hao, Chuan-Ming, Huashan Hospital Fudan University, Shanghai, China
Background
Complement activation plays a central role in the pathogenesis of IgA nephropathy (IgAN), but the contribution of complement regulatory mechanisms remains incompletely understood. We evaluated the clinical and prognostic significance of glomerular complement receptor 1 (CR1) expression and explored whether integrating CR1 with C4b improves risk stratification.
Methods
In this study, 86 patients with biopsy-proven IgAN were included. Glomerular CR1 expression was quantified by immunohistochemistry. Associations with baseline clinical and pathologic features were assessed using regression models. Among 55 patients with follow-up, time to clinical remission was analyzed using Kaplan–Meier curves and Cox models. In a subset with available C4b data (n=31), a combined CR1–C4b phenotype was used to evaluate complement regulation and activation jointly.
Results
Low CR1 expression was associated with more severe baseline disease, including lower eGFR, higher proteinuria, and greater pathologic injury, and delayed remission. However, these associations were attenuated after adjustment for established clinical and pathologic variables. The combined CR1–C4b phenotype identified a high-risk subgroup (CR1-low/C4b-positive) with significantly delayed remission (median 38 vs 11 months, p=0.0034; adjusted HR 0.14, 95% CI 0.03–0.60). Addition of this phenotype to a clinical model including eGFR and proteinuria improved model discrimination (C-index 0.64 to 0.71) and showed a trend toward improved model fit.
Conclusion
Glomerular CR1 expression reflects baseline disease severity in IgAN. Integrating CR1 expression with C4b identifies a subgroup with delayed remission and may improve risk stratification.
Association of the CR1-low/C4b-positive phenotype with time to remission in patients with IgAN.
| HR (95% CI) | P value | |
| Unadjusted | 0.304 (0.107, 0.863) | 0.025* |
| Model 1 | 0.304 (0.107, 0.863) | 0.011* |
| Model 2 | 0.136 (0.031, 0.595) | 0.008* |
| Model 3a | 0.136 (0.031, 0.595) | 0.010* |
| Model 3b | 0.136 (0.031, 0.595) | 0.006* |
Model 1: age, sex. Model 2: Model 1 + baseline eGFR + log(1+24-h proteinuria). Model 3a: Model 2 + Oxford T. Model 3b: Model 2 + immunosuppressant use. *P<0.05.