Abstract:

Objective: The aim of this study is to explore the application of heat antigen retrieval combined with pepsin digestion on immunofluorescence (IF) staining for paraffin embedded human renal tissues. Methodology: Renal-biopsy proved 9 groups of glomerular diseases from Research Institute of Nephrology, Jinling Hospital were enrolled, they were membranous nephropathy (n=6), membranoproliferative glomerulonephritis (n=5), lupus nephritis including class IV(n=2) and class IV+V(n＝2), IgA nephropathy(n =12), anti-GBM disease(n=4)，dense deposit disease（n=4）, acute poststreptococcal glomerulonephritis (n=6), light-chain deposition disease (kappa) (n=4), and primary amyloid (lambda) (n=4). Paraffin -embedded sections of renal biopsy tissues were processed by using heat antigen retrieval with pressure cooke (EDTA, pH=8.0) combined with pepsin digestion and immunofluorescence staining of IgG, IgA, IgM, C3, C1q, κ、λ light chain. And then we compare the immunofluoresence staining of frozen sections (IF-F) with heat antigen retrieval combined with pepsin digestion paraffin-embedded sections (IF-P). Results: IF-P of IgG , IgA, and C1q, was in accordance with that of frozen sections in positive rate, distribution pattern and staining intensity. IF-P of IgM and C3 was the same with IF-F in distribution pattern. However, the intensity and positive rate was inferior to IF-F, which was not influent on diagnosis. One hundred percent of diagnostic accordance rate was obtained in IF-P. Furthermore, the structure of paraffin sections were clearer than that of frozen sections, which led to more easier judgment of the location of immunecomplex deposits. Conclusion: IF-P is a good alternative for immunofluoresence staining in the condition of frozen tissues without glomerula. This method is useful for retrospective study on paraffin-embedded sections of renal biopsy tissues.