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Analyses of Proteinuria, Renal Infiltration of Leukocytes, and Renal Deposition of Proteins in Lupus-prone MRL/lpr Mice
Published on: June 8, 2022
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Study of the variables associated with local complement activation in IgA nephropathy
Alfons Segarra-Medrano1, Clara Carnicer-Caceres2, Naiara Valtierra-Carmeno1
1Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España.
Summary
Urinary C4d and MBL levels are linked to mesangial deposits in IgA nephropathy. These urinary markers show promise for identifying patients with specific complement deposits.
Area of Science:
- Nephrology
- Immunology
- Complement System
Background:
- Idiopathic IgA nephropathy is a common cause of glomerulonephritis.
- The complement system, particularly the lectin pathway, plays a role in IgA nephropathy pathogenesis.
- Mesangial deposits of complement proteins are characteristic of IgA nephropathy.
Purpose of the Study:
- To identify variables associated with urinary properdin, MBL, C4d, and C5b-9 in IgA nephropathy.
- To evaluate the utility of urinary MBL and C4d for detecting mesangial deposits.
Main Methods:
- Studied 96 IgA nephropathy patients, recording clinical and biochemical data.
- Quantified renal lesions using the Oxford classification.
- Performed immunohistochemistry on biopsies and measured urinary complement proteins (properdin, MBL, C4d, C5b-9).
Main Results:
- Urinary C4d and MBL levels were predicted by mesangial deposits and proteinuria.
- Urinary C5b-9 levels were predicted by MBL, properdin, and proteinuria.
- Urinary C4d achieved 90% sensitivity and 73% specificity for mesangial C4d deposits.
- Urinary MBL achieved 83.9% sensitivity and 81.6% specificity for mesangial MBL deposits.
Conclusions:
- Mesangial deposits are the primary predictor of urinary C4d and MBL concentrations.
- Urinary MBL may indicate lectin pathway activation in the tubular lumen.
- Urinary MBL and C4d are potential sensitive and specific biomarkers for mesangial deposits in IgA nephropathy.
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