title: Immunohistochemical identification of HCV target antigen in paraffin-embedded liver tissue: reproducibility and staining patterns.
abstract: BACKGROUND
  Immunohistochemical staining has been applied successfully to detect hepatitis C virus (HCV) antigen in fresh frozen tissue. In paraffin-embedded tissues, however, minimal trials with conflicting results have been reported.
  
  
  OBJECTIVE
  The present study is a trial to evaluate the identification of HCV antigen in paraffin-embedded liver biopsies using the anti-HCV monoclonal antibody (MAb) TORDJI-22.
  
  
  METHODS
  We applied immunohistochemical staining for HCV in 56 paraffin-embedded liver biopsy specimens, 46 from patients seropositive for HCV-RNA and 10 control liver biopsy specimens. The TORDJI-22 MAb was applied in dilution 1:40, with overnight incubation.
  
  
  RESULTS
  Reproducible staining patterns of HCV antigen in tissues were identified among the majority (42/46-91%) of HCV RNA seropositive cases. The staining pattern was cytoplasmic of hepatocytes, with occasional nuclear hue. It is mainly coarse granular with microvesicular pattern. Three staining patterns were identified: A, diffuse or membranous; B, patchy; and C, occasional paranuclear. None of the control samples showed a similar staining pattern.
  
  
  CONCLUSIONS
  Immunohistochemical identification of HCV antigen is easy to apply in paraffin-embedded liver biopsy specimens when the optimal detection techniques are applied. The staining pattern is reproducible, being mainly coarse granular cytoplasmic. Cross reactivity with hepatitis B virus antigens was not detected.
authors.affiliation: Department of Internal medicine, Mansoura University, Mansoura , 35516, Egypt. g_shiha@hotmail.com
authors.forename: Gamal E
authors.initials: GE
authors.lastname: Shiha
authors.forename: Khaled R
authors.initials: KR
authors.lastname: Zalata
authors.forename: Ahmed F
authors.initials: AF
authors.lastname: Abdalla
authors.forename: Mostfa K
authors.initials: MK
authors.lastname: Mohamed
mesh_terms: D001707:Biopsy, Needle; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000473:pathology*; D018937:Hepatitis C Antibodies; D018936:Hepatitis C Antigens / Q000032:analysis / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D016612:Paraffin Embedding; D011336:Probability; D012367:RNA, Viral; D012016:Reference Values; D015203:Reproducibility of Results; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D018937:Hepatitis C Antibodies; D018936:Hepatitis C Antigens; D012367:RNA, Viral