title: [Use of paraffin sections for immunofluorescence staining in renal biopsy].
abstract: OBJECTIVE
  To explore the best method for detecting immunoglobulin, HBsAg and HBcAg in formalin-fixed  paraffin-embedded renal biopsy tissues by immunofluorescence (IF).
  
  
  METHODS
  In the study, 45 cases of renal  biopsy were collected, including 20 cases of immunoglobulin A (IgA) nephropathy, 15 cases of membranous  nephropathy and 10 cases of membranous type hepatitis B virus associated nephritis. IgG, IgA, HBsAg and HBcAg  depositions were evaluated in these cases by IF with different antigen retrieval methods and different periods of  antibody incubation time. The results were compared with IF on frozen tissues from the same set of cases to  evaluate the methodology.
  
  
  RESULTS
  All the cases were negative with heat-induced epitope retrieval alone.  Immunoglobulin, HBsAg and HBcAg were more readily identifiable after digestion with trypsin than with pepsin. IgG  and IgA were best visualized after 30 min of digestion with trypsin and 90 min of incubation with primary  antibody for IgG and IgA. HBsAg and HBcAg were best visualized after 30 min of incubation with primary antibody  and 150 min of incubation with secondary antibody. Comparing immunoglobulins, HBsAg and HBcAg on fresh sections  and paraffin sections, their visualizations were almost identical with both techniques although the signal on  paraffin sections was slightly weaker than that on fresh theretsections.
  
  
  CONCLUSIONS
  Trypsin-digested paraffin  sections may be used for diagnosis of renal disease whether there are false negative results.
authors.affiliation: Department of Pathology, Peking University School of Basic Medical Sciences, Beijing 100191, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Hai-jing
authors.initials: HJ
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Lu
mesh_terms: D000936:Antigen-Antibody Complex; D001706:Biopsy; D005455:Fluorescent Antibody Technique / Q000379:methods*; D005629:Frozen Sections; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D007668:Kidney / Q000276:immunology / Q000473:pathology*; D007674:Kidney Diseases / Q000276:immunology / Q000473:pathology*; D016612:Paraffin Embedding
chemical_list: D000936:Antigen-Antibody Complex; D007136:Immunoglobulins