Treatment of Dense Deposit Disease with Positive C3 Nephritic Factor (C3NeF) and No CFH Gene Mutation
Clinical Scenario
First-line protocol
This protocol addresses patients with dense deposit disease who test positive for C3 nephritic factor (C3NeF), have no identified mutation in the complement factor H gene (CFH), and demonstrate evidence of C3 consumption — reflected by low serum C3 levels.
Why This Profile Matters
Positivity for C3NeF alongside evidence of ongoing C3 consumption and the absence of a CFH mutation identifies a specific patient population for whom a targeted, evidence-supported treatment approach is available. This constellation of findings informs the choice and sequence of intervention.
Treatment Approach — Partial Overview
Management involves a plasma-based strategy to address the C3NeF autoantibody, combined with a targeted anti-B cell therapy.
Full regimen, monitoring criteria, and decision thresholds are available via the structured protocol below.
Treatment Goals
The primary aim is maintenance or prevention of decline in renal function, assessed by degree of proteinuria and hematuria. Secondary goals include reduction in C3NeF levels and normalization of alternative complement pathway activity, tracked by C3/C3d ratios.
References
DOI: 10.1681/ASN.2007030356
- The use of rituximab may be justified in patients who are positive for C3NeF, do not have a mutation in CFH, and show evidence of C3 consumption (Figure 4).
- In the presence of C3NeF, removal or dilution of the autoantibody should be considered via plasma exchange or infusion, and anti–B cell agents such as rituximab might be valuable.
- Standard rituximab protocols for the treatment of renal disease should be used, following C3NeF levels and complement assays to document any response.
- The primary criterion for success at the end of this period should be prevention of disease progression (either maintenance of or prevention of decrease in renal function) as measured by the degree of proteinuria/hematuria.
- Secondary criteria for success should be normalization of activity levels of the alternative complement pathway and reduction in C3NeF levels (Figure 4).
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