Kidney Week

Abstract: TH-PO0477

C3 Hypocomplementemia at Diagnosis of IgAN Is Associated with a More Severe Clinical and Histopathological Phenotype

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

• Gourdoupari, Eftychia Eirini Maria, Clinical & Interventional Nephrology Unit, 2nd Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens (NKUA), Attikon University Hospital, Athens, Greece

Eftychia Eirini Maria Gourdoupari, MD

• Gkika, Vasiliki, Clinical & Interventional Nephrology Unit, 2nd Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens (NKUA), Attikon University Hospital, Athens, Greece

Vasiliki Gkika, MD, MSc

• Koukoulaki, Maria, Department of Nephrology, Nikaia-Piraeus General Hospital “Agios Panteleimon”, Nikaia, Greece

Maria Koukoulaki, MD, PhD

• Chelioti, Eleni, Department of Nephrology, Tzaneio General Hospital of Piraeus, Piraeus, Greece

Eleni Chelioti, MD, PhD

• Pantzopoulou, Evangelia, Clinical & Interventional Nephrology Unit, 2nd Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens (NKUA), Attikon University Hospital, Athens, Greece

Evangelia Pantzopoulou, MD

• Tsaousi, Spyridoula S., Clinical & Interventional Nephrology Unit, 2nd Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens (NKUA), Attikon University Hospital, Athens, Greece

Spyridoula S. Tsaousi, MD

• Zermpala, Synodi, Department of Nephrology, Nikaia-Piraeus General Hospital “Agios Panteleimon”, Nikaia, Greece

Synodi Zermpala, DrMed

• Kalaitzidis, Rigas, Department of Nephrology, Nikaia-Piraeus General Hospital “Agios Panteleimon”, Nikaia, Greece

Rigas Kalaitzidis, MD

• Liapis, Georgios, First Department of Pathology, Laiko General Hospital, National and Kapodistrian University of Athens (NKUA), Athens, Greece

Georgios Liapis

• Lionaki, Sophia, Clinical & Interventional Nephrology Unit, 2nd Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens (NKUA), Attikon University Hospital, Athens, Greece

Sophia Lionaki, MD, PhD

Background

IgA nephropathy (IgAN) is characterized by considerable heterogeneity in clinical presentation and prognosis. In the context of identifying prognostic biomarkers, we investigated the potential association between serum complement C3 levels with the clinical and histopathological phenotype of the disease.

Methods

A case-control study was conducted including patients with biopsy-proven IgAN and C3 hypocomplementemia at diagnosis. For each patient, five controls with normal serum C3 levels were selected matched for age and sex (1:5 matching). Clinical phenotypes at presentation were categorized as follows: i) isolated microscopic hematuria (mild), ii) hematuria with proteinuria (moderate), and iii) hematuria, proteinuria, and impaired renal function (severe).

Results

A total of 54 patients were included, with an age of 47.5 years (IQR: 23); 24 patients (44%) were males. At diagnosis, estimated GFR (eGFR) was 83.5 mL/min/1.73 sqm (IQR: 64), while 24-hour proteinuria was 890 mg (IQR: 1790). Patients with C3 hypocomplementemia at diagnosis of IgaN exhibited an approximately 5-fold increased likelihood (OR=4.57) of presenting with a more severe clinical phenotype characterized by hematuria, proteinuria, and impaired renal function compared to patients with normal C3 levels. Furthermore, a clear trend toward an association between C3 hypocomplementemia and more severe histopathological lesions was observed (Table 1).

Conclusion

Patients with C3 hypocomplementemia at IgAN diagnosis appear to present with more severe clinical phenotype and advanced histopathological injury compared to patients with normal C3 levels.

Table 1: Association between Low Serum C3 Levels and clinical picture in patients with IgAN at diagnosis