Related Experiment Video
Updated: Jun 21, 2026
Analyses of Proteinuria, Renal Infiltration of Leukocytes, and Renal Deposition of Proteins in Lupus-prone MRL/lpr Mice
Published on: June 8, 2022
Immunofluorescence on paraffin-embedded sections in evaluation of immune complex deposits in renal biopsy specimens
Małgorzata Wagrowska-Danilewicz1, Marian Danilewicz
1Department of Nephropathology, Medical University of Lodz, Lodz. emwude@poczta.onet.pl
Insights
Immunofluorescence on paraffin-embedded kidney sections is less sensitive than on frozen sections for detecting immune deposits. This method may overlook certain glomerulopathies, making frozen sections essential for accurate renal biopsy assessment.
Area of Science:
- Nephrology
- Pathology
- Immunohistochemistry
Background:
- Immunofluorescence (IF) on paraffin-embedded tissue sections for detecting immune complex deposits in renal biopsies yields controversial results.
- Reproducibility remains a challenge, impacting diagnostic accuracy in glomerulopathies.
Purpose of the Study:
- To evaluate the diagnostic utility of direct immunofluorescence on paraffin-embedded renal sections.
- To compare its sensitivity and specificity against immunofluorescence on frozen sections for detecting immune deposits in IgA nephropathy, membranous glomerulopathy, and lupus nephritis.
Main Methods:
- Direct immunofluorescence was performed on paraffin-embedded renal sections pre-treated with proteinase K (30 or 60 min) and on corresponding frozen sections.
- Detection of IgA, IgG, IgM, and C3 deposits was analyzed in 24 IgA nephropathy, 22 membranous glomerulopathy, and 24 lupus nephritis cases.
Main Results:
- Immunofluorescence on paraffin sections demonstrated significantly lower sensitivity for IgA, IgG, IgM, and C3 detection compared to frozen sections.
- Agreement rates between paraffin and frozen sections were suboptimal: IgA (56.5%), IgM (44.4%), IgG (73.9%), and C3 (51.5%).
- Only 41.7% of IgA nephropathy cases showed dominant or co-dominant IgA fluorescence on paraffin sections.
Conclusions:
- Direct immunofluorescence on paraffin-embedded renal sections is less sensitive and cannot replace immunofluorescence on frozen sections for diagnosing glomerulopathies.
- Results from paraffin-embedded sections should be interpreted with caution due to potential underestimation of immune complex deposition.
- Frozen sections remain the gold standard for immunofluorescence assessment in renal biopsies.
Abstract:
The data focused on the value of immunofluorescence on paraffin-embedded sections are controversial, and it is still difficult to obtain reproducible results. The aim of our study was to evaluate the usefulness of immunofluorescence on paraffin-embedded renal section in detecting immune complex deposits in IgA nephropathy (n = 24), membranous glomerulopathy (n = 22) and lupus nephritis (n = 24). Our study revealed that direct immunofluorescence on paraffin-embedded sections pre-treated with proteinase K for 30 or 60 min is a less sensitive method than immunofluorescence on frozen sections; therefore a number of glomerulopathies may be overlooked. Immunofluorescence on paraffin sections showed dominant or co-dominant fluorescence of Riga only in 41.7% of cases of Riga nephropathy. In the studied glomerulopathies the number of positive immunofluorescences of IgA, IgG, IgM and C3 was significantly lower in immunofluorescence on paraffin sections in comparison with findings obtained from immunofluorescence on frozen sections. Irrespective of glomerular disease the rate of agreement between immunofluorescence on paraffin sections and immunofluorescence on frozen sections with respect to the presence of IgA was 56.5%, IgM - 44.4%, IgG - 73.9%, and C3 - 51.5%. In conclusion, our study revealed that immunofluorescence on paraffin sections cannot replace immunofluorescence on frozen sections in the assessment of human renal biopsies, and must be interpreted with great caution.
