title: Immunohistochemical detection of immunoglobulins and complements in formaldehyde-fixed and paraffin-embedded renal biopsy tissues; an adjunct for diagnosis of glomerulonephritis.
abstract: BACKGROUND
  The present study was undertaken to demonstrate the deposition of immunoglobulins or complements in formaldehyde-fixed and paraffin-embedded renal biopsy tissues through the unmasking of antigens with microwave treatment plus protease digestion or trypsin digestion.
  
  
  METHODS
  Biopsy samples from patients with IgA nephritis (n = 7), lupus nephritis (7), membranous nephropathy (7) and mesangiocapillary glomerulonephritis (3) were used. Antigen unmasking was performed with (i) microwave treatment plus protease digestion for 10, 30 or 60 min, or (ii) digestion with 0.25% trypsin for 60 or 120 min.
  
  
  RESULTS
  Microwave treatment plus protease digestion for 30 or 60 min and trypsin digestion for 120 min provided good results for the unmasking of immunoglobulins in glomeruli with structural preservation. The IgA deposits in IgA nephritis and IgG deposits in lupus nephritis and membranous nephropathy were clearly revealed in more than 80% of cases by both pretreatments. Microwave treatment plus protease digestion for 30 min revealed the deposition of C3 in all cases of mesangiocapillary glomerulonephritis and lupus nephritis and was superior to trypsin digestion. Characteristic patterns of C3 deposition were observed for these forms of glomerulonephritis, although C3 deposits in membranous nephropathy were detected in only 50% of cases. It was not possible to unmask all of the antigens in the glomeruli, especially those with weak immunofluorescence.
  
  
  CONCLUSIONS
  Microwave treatment plus protease digestion is effective for the unmasking of antigens in paraffin sections and as useful for the diagnosis of immune-mediated glomerulonephritis as trypsin digestion.
authors.affiliation: Department of Histopathology, Shaheed Ziaur Rahman Medical College, Bogra, Bangladesh.
authors.forename: Akm Rownak Hossain
authors.initials: AR
authors.lastname: Chowdhury
authors.forename: Takashi
authors.initials: T
authors.lastname: Ehara
authors.forename: Makoto
authors.initials: M
authors.lastname: Higuchi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hora
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Shigematsu
mesh_terms: D001706:Biopsy; D015922:Complement C1q / Q000378:metabolism; D003176:Complement C3 / Q000378:metabolism*; D005404:Fixatives; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D005557:Formaldehyde; D005921:Glomerulonephritis / Q000276:immunology* / Q000473:pathology*; D005922:Glomerulonephritis, IGA / Q000276:immunology / Q000473:pathology; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology / Q000473:pathology; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D007136:Immunoglobulins / Q000378:metabolism*; D007668:Kidney / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008181:Lupus Nephritis / Q000276:immunology / Q000473:pathology; D008872:Microwaves; D016612:Paraffin Embedding
chemical_list: D003176:Complement C3; D005404:Fixatives; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D005557:Formaldehyde; D015922:Complement C1q