Nephritic factor C3 (C3NeF) – autoantibody testing0802
Nephritic factors include a heterogeneous group of autoantibodies against neoepitopes formed in the C3 and C5 convertases of the complement system, causing dysregulation of this system. The nephritic factor C3 (C3NeF) stabilizes the C3 convertase of the alternative pathway, affecting the development of kidney diseases. There are also other nephritic factors that stabilize the C5 convertase (C5NeF) and the convertases of the classical and lectin pathways (C4NeF).
AGGL (Agglutination test) – qualitative determination.
- Glomerulonephritis
- Blood collection in the morning on an empty stomach from 8 to 11 a.m. or 4-5 hours after the last meal.
- Avoid fatty foods 24 hours before the test.
- Children under 1 year – do not eat 30-40 minutes before the test.
- Children 1-5 years – do not eat 2-3 hours before the test.
- Before blood collection, drink 1–2 glasses of clean still water (for children – portions up to 150-200 ml over 30 minutes).
- Blood collection should be done before taking medications; indicate medication intake in the referral.
- Avoid physical exertion, stress, and do not smoke 30 minutes before the test.
Autoantibodies C3NeF are associated with kidney diseases such as C3 glomerulopathy (C3G) and membranoproliferative glomerulonephritis (MPGN), which are accompanied by immune complexes. They are also found in infections and autoimmune disorders, including systemic lupus erythematosus and acquired partial lipodystrophy. A characteristic feature is C3 hypocomplementemia. C3 glomerulopathy includes dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). Secondary MPGN manifests as immune complex deposits in the kidney glomeruli against the background of systemic diseases.