C3 Glomerulopathy and post-infectious glomerulonephritis define a disease spectrum

Area of Science:

• Nephrology
• Pediatric Nephrology
• Immunology

Background:

• Post-infectious glomerulonephritis (PIGN) typically has a benign course, but severe presentations involve complement alternative pathway (CAP) dysregulation.
• C3 glomerulopathy (C3G), also linked to CAP dysregulation, shares histopathological features with PIGN but has a worse outcome.
• A potential disease spectrum exists between PIGN and C3G, with historical misclassification of C3G as PIGN.

Purpose of the Study:

• To investigate the hypothesis that PIGN and C3G represent a disease spectrum.
• To compare the clinical courses and outcomes of children with PIGN and those reclassified as C3G.

Main Methods:

• Retrospective review of 33 children diagnosed with PIGN between 1985-2010 who had renal biopsies.
• Reclassification of 8 children into C3G based on current criteria.
• Outcome assessment based on proteinuria, C3 levels, and renal function.

Main Results:

• Sixteen (72.7%) children with typical PIGN achieved complete recovery.
• Only 2 (25%) children reclassified as C3G had a favorable outcome.
• Despite more severe initial presentation in typical PIGN, long-term outcomes were better compared to C3G.

Conclusions:

• Findings support PIGN and C3G as part of a disease spectrum.
• Distinguishing between PIGN and C3G is crucial for determining long-term clinical implications.
• Different management strategies are indicated for PIGN and C3G based on their distinct outcomes.