C3 glomerulopathy: a new classification

Area of Science:

• Nephrology
• Immunology
• Complement System Biology

Background:

• Glomerular inflammation is often linked to complement system dysregulation, particularly the alternative pathway.
• A common pathological finding is complement C3 deposition in glomeruli without significant immunoglobulin presence.
• This suggests underlying genetic or acquired complement dysregulation in affected patients.

Purpose of the Study:

• To summarize current understanding of complement dysregulation and glomerular inflammation.
• To propose a new classification term, C3 glomerulopathy, for specific glomerular pathologies.
• To highlight the importance of screening for complement regulatory abnormalities.

Main Methods:

• Review of existing literature on complement system and glomerular diseases.
• Analysis of pathological findings characterized by isolated C3 deposition.
• Synthesis of evidence linking complement dysregulation to specific kidney pathologies.

Main Results:

• Isolated glomerular C3 deposition, in the absence of significant immunoglobulin, signifies a distinct pathological entity.
• The term C3 glomerulopathy is proposed to encompass these conditions.
• This classification prompts consideration of complement system screening.

Conclusions:

• C3 glomerulopathy is a proposed classification for glomerular diseases with isolated C3 deposition.
• Identifying C3 glomerulopathy aids in detecting complement dysregulation.
• This may lead to identifying patients eligible for complement-targeted therapies.