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Isolation of Glomeruli and In Vivo Labeling of Glomerular Cell Surface Proteins
Published on: January 18, 2019
C4d immunohistochemistry in membranous nephropathy
Monalisa Hui1, Megha S Uppin1, Aruna K Prayaga1
1Department of Pathology, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India.
Background:
Membranous nephropathy (MN) is the most common cause of nephropathy in adults. The diagnosis is based on characteristic light microscopic, electron microscope and immunofluorescence (IF) findings. In early MN, the light microscopic findings may be difficult to differentiate from minimal chain disease. In the absence of fresh frozen tissue for IF, immunohistochemistry with C4d aids in the diagnosis.
Materials And Methods:
A total 48 cases of MN diagnosed on renal biopsy were analyzed. The formalin fixed paraffin embedded tissues were stained with routine hematoxylin and eosin stains along with periodic acid-Schiff and silver methenamine stains to highlight the basement membrane. Fresh frozen tissues were available for IF in 40 cases. Immunostaining with C4d was done on paraffin-embedded sections by polymer-Horse Radish Peroxidase (HRP) technique using polyclonal antiserum to C4d (Biogenex, India).
Results:
There were 25 cases of idiopathic MN, 17 cases of Class V lupus nephritis and 2 cases were secondary to hepatitis C infection with cirrhosis. The glomerular basement membrane (GBM) was diffusely thickened with formation of spikes in 28 cases. In 11 cases the capillary loops were rigid but spikes were not seen and in 9 cases there was no apparent thickening of the basement membrane. All the cases showed diffuse positivity for C4d along the GBM.
Conclusion:
C4d is a reliable method to establish the diagnosis of MN and also a sensitive marker of complement activation reflecting the pathogenesis of MN.
Insights
Immunohistochemistry with C4d aids in diagnosing membranous nephropathy (MN) when immunofluorescence is unavailable. C4d staining is a reliable marker for MN diagnosis and complement activation.
Area of Science:
- Nephrology
- Pathology
- Immunology
Background:
- Membranous nephropathy (MN) is the leading cause of adult nephropathy.
- Diagnosis relies on microscopy and immunofluorescence (IF).
- Early MN can mimic minimal change disease, complicating diagnosis without IF.
Purpose of the Study:
- To evaluate C4d immunohistochemistry as a diagnostic tool for MN.
- To assess C4d's role when fresh frozen tissue for IF is absent.
- To correlate C4d positivity with complement activation in MN pathogenesis.
Main Methods:
- Analyzed 48 renal biopsy cases of MN.
- Used routine stains (H&E, PAS, silver methenamine) on paraffin-embedded tissues.
- Performed C4d immunohistochemistry on paraffin sections (polymer-HRP technique).
- IF was available for 40 cases.
Main Results:
- Included idiopathic MN (25), lupus nephritis (17), and hepatitis C-related MN (2).
- Observed GBM thickening with spikes (28), rigid loops without spikes (11), or no thickening (9).
- All cases demonstrated diffuse C4d positivity along the glomerular basement membrane (GBM).
Conclusions:
- C4d immunohistochemistry is a reliable method for diagnosing MN.
- C4d serves as a sensitive marker of complement activation in MN.
- This technique aids diagnosis when IF is not feasible.
