Acquired drivers of C3 glomerulopathy

Area of Science:

• Nephrology
• Immunology
• Complement System Biology

Background:

• C3 glomerulopathy (C3G) is a rare kidney disease driven by complement alternative pathway (AP) dysregulation.
• Diagnosis involves kidney biopsy showing C3 deposition, distinguishing dense deposit disease (DDD) and C3 glomerulonephritis (C3GN).
• Acquired autoantibodies, nephritic factors (NFs), stabilize complement convertases, causing overactivation.

Purpose of the Study:

• To review acquired drivers of C3G, focusing on nephritic factors (NFs).
• To highlight challenges in C3G diagnosis and treatment.
• To identify research gaps concerning NF origins, mechanisms, and pathogenic roles.

Main Methods:

• Review of literature on C3G pathogenesis, focusing on acquired drivers.
• Emphasis on autoantibodies like C3Nefs and C5Nefs.
• Discussion of diagnostic challenges and current therapeutic limitations.

Main Results:

• Nephritic factors (C3Nefs, C4Nefs, C5Nefs) are key acquired drivers of AP dysregulation in C3G.
• Existing therapies, including eculizumab, show limited efficacy.
• Variability in autoantibody detection and lack of standardized assays complicate clinical interpretation.

Conclusions:

• Acquired drivers, particularly nephritic factors, are central to C3G pathogenesis.
• Further research is needed to understand NF origins, mechanisms, and therapeutic targeting.
• Comprehensive assessment including autoantibodies, biomarkers, and genetics is crucial for understanding C3G.