title: Diagnostic utility of IgG and IgM immunohistochemistry in autoimmune liver disease.
abstract: OBJECTIVE
  To assess the role of IgM and IgG immunohistochemistry (IHC) in the evaluation of autoimmune liver conditions--autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC).
  
  
  METHODS
  Forty one biopsies from untreated patients diagnosed with autoimmune liver disease (AIH, n = 20; PBC, n = 13; PSC, n = 8) and fourteen biopsies of patients with chronic hepatitis C were selected. IgM and IgG-positive plasma cells were counted in each sample.
  
  
  RESULTS
  A predominance of IgG-positive plasma cells was seen in AIH (90% of cases), PSC (75% of cases), and chronic hepatitis C (100% of cases), while IgM-positive plasma cells predominated in PBC (92.8% of cases). The IgM /IgG ratio (< 1 or > or = 1) accurately distinguished PBC from AIH in 90.9% of cases (sensitivity = 92.3%, specificity = 90%), and PBC from either AIH or PSC in 87.8% of cases (sensitivity = 92.3%, specificity = 85.7%).
  
  
  CONCLUSIONS
  Plasmacytic infiltrates expressing predominantly IgM are characteristic of PBC, while other forms of liver disease analyzed in this study, including AIH, typically show an IgG-predominant plasma cell infiltrate. Our data indicate that IgM and IgG IHC may be a useful tool when PBC is a diagnostic consideration.
authors.affiliation: Department of Pathology, Columbia University College of Physicians & Surgeons, 630 W168th Street VC14-238B, New York, NY 10032, USA. rkm2124@columbia.edu
authors.forename: Roger Klein
authors.initials: RK
authors.lastname: Moreira
authors.forename: Frank
authors.initials: F
authors.lastname: Revetta
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Koehler
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Washington
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D015209:Cholangitis, Sclerosing / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D019693:Hepatitis, Autoimmune / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007075:Immunoglobulin M / Q000378:metabolism*; D007150:Immunohistochemistry; D008099:Liver / Q000276:immunology / Q000473:pathology; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000378:metabolism; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M