Kidney Week

Abstract: TH-PO0921

Clinical Significance of Complement C3 Deposition in Post-Transplant IgAN

Session Information

• Transplantation: Clinical - Glomerular Diseases, Infections, and Rejection
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2102 Transplantation: Clinical

Authors

• Gogulapati, Anusha, University of California Davis School of Medicine, Sacramento, California, United States

Anusha Gogulapati

• Jen, Kuang-Yu, University of California Davis School of Medicine, Sacramento, California, United States

Kuang-Yu Jen, MD, PhD

• Ndife, Briana C., Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States

Briana C. Ndife, MPH

• Trenz, Helen, Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States

Helen Trenz, PhD

• Srinivas, Titte, Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States

Titte Srinivas, MD, MBBS, MBA

• Moradi, Hamid, Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States

Hamid Moradi

• Shaikh, Sana J., University of California Davis School of Medicine, Sacramento, California, United States

Sana J. Shaikh, MD

Background

Kidney biopsies of patients (pts) with immunoglobulin A nephropathy (IgAN) often reveal mesangial complement C3 deposits, which have prognostic value in native kidneys. This retrospective study assessed clinical implications of C3 deposition in post-transplant (PT) IgAN.

Methods

Pts with PT IgAN at UC Davis (2016–2023) were included. From baseline (first PT biopsy confirming diagnosis), pts were grouped with/without C3 using an immunofluorescence intensity threshold for C3 ≥2+. Primary outcome was proportion of pts meeting a renal composite endpoint (≥30% eGFR decline, eGFR <15 mL/min/1.73 m², or dialysis dependence) at diagnosis of PT IgAN. Secondary outcomes were change in eGFR from baseline, proteinuria levels, and clinical disease recurrence (proteinuria ≥1 g/g, microscopic hematuria, or ≥40% eGFR decline) over 36 months (mo).

Results

Of 64 pts with PT IgAN, 24 had C3. Baseline pt demographics, eGFR, and treatments were similar between groups. At baseline, pts with C3 had significantly stronger IgA staining (3+, 70.8% vs 15.0%; 2+, 29.2% vs 85.0%; P<0.001), increased mesangial hypercellularity (M1, 79.2% vs 47.5%; M0, 20.8% vs 52.5%; P=0.018), and higher proteinuria (Fig 1) vs pts without C3. The primary outcome occurred in 1 pt without C3 and 2 pts with C3 (P=0.314). Proteinuria was significantly higher in the C3 group at 24 mo (P=0.010). By 36 mo, more pts with C3 had nephrotic range proteinuria; this was not statistically significant. Over 36 mo, the C3 group trended toward worse eGFR decline and increased clinical disease recurrence; these trends were not statistically significant.

Conclusion

In PT IgAN, C3 deposition is associated with significantly higher proteinuria at diagnosis and a trend toward higher proteinuria over time, suggesting C3 deposits may be associated with more aggressive disease. Sample sizes were limited, highlighting a need for larger studies.

Funding

• Commercial Support – Novartis Pharmaceutical Corporation

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025t5beckw1