title: Immunofluorescence on pronase-digested paraffin sections: a valuable salvage technique for renal biopsies.
abstract: Direct immunofluorescence (IF) on frozen tissue is the method of choice for the study of medical renal diseases. When no glomeruli are available, IF can be performed on the formalin-fixed paraffin-embedded tissue allocated for light microscopy after antigen retrieval with proteases. In this study, the results of IF on frozen tissue (IF-F) and on deparaffinized, pronase-treated tissue (IF-P) were compared in 71 renal biopsies representing 12 major renal diseases. Using IF-P, diagnostic findings were obtained in 100% of cases of lupus nephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, fibrillary glomerulonephritis, primary amyloidosis, myeloma cast nephropathy, and light-chain Fanconi syndrome (LCFS), 88% of cases of immunoglobulin (Ig)A nephropathy, 80% of cases of light-chain deposition disease, 60% of cases of membranoproliferative glomerulonephritis type 1, 50% of cases of idiopathic membranous glomerulopathy (MGN) and 20% of cases of anti-glomerular basement membrane (GBM) disease. IF-P was less sensitive than IF-F for the detection of C3 in all disease categories and for the detection of IgG in cases of MGN and anti-GBM disease. The diagnostic kappa light-chain staining was demonstrated in 100% of cases of LCFS by IF-P versus 40% by IF-F. We conclude that IF-P is a valuable salvage immunohistochemical technique for renal biopsies lacking adequate cortical sampling for IF-F, and is superior to IF-F for the diagnosis of LCFS.
authors.affiliation: Department of Pathology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA. sn386@columbia.edu
authors.forename: S H
authors.initials: SH
authors.lastname: Nasr
authors.forename: S J
authors.initials: SJ
authors.lastname: Galgano
authors.forename: G S
authors.initials: GS
authors.lastname: Markowitz
authors.forename: M B
authors.initials: MB
authors.lastname: Stokes
authors.forename: V D
authors.initials: VD
authors.lastname: D'Agati
mesh_terms: D000936:Antigen-Antibody Complex; D001706:Biopsy; D005455:Fluorescent Antibody Technique / Q000379:methods*; D005629:Frozen Sections; D006801:Humans; D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains; D007668:Kidney / Q000276:immunology / Q000473:pathology*; D007674:Kidney Diseases / Q000276:immunology / Q000473:pathology*; D016612:Paraffin Embedding; D011402:Pronase; D012680:Sensitivity and Specificity
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains; D011402:Pronase