Abstract
Dense tissue infiltrates of IgG4+ plasma cells >50/high-powered field (HPF) are purportedly highly specific for IgG4-related disease. However, the frequency and significance of liver-infiltrating IgG4+ plasma cells in primary sclerosing cholangitis (PSC) applying these cut-offs has not been determined. We sought to determine the incidence of intrahepatic IgG4-positive staining in PSC patients undergoing transplantation, correlating findings with clinical parameters. Immunohistochemical staining was performed on liver explants obtained between 1991 and 2009. Of 122 explants obtained, hilar IgG4+ staining was found to be mild (10–29 IgG4+ cells/HPF) in 23.0%, moderate (30–50/HPF) in 9.0% and marked (>50/HPF) in 15.6%. Marked hilar lymphoplasmacytic infiltration was significantly associated with marked hilar IgG4+ staining (P < 0.001). No patient had marked peripheral IgG4+ staining, although mild and moderate staining was observed in 24.5% and 3.3% respectively. Marked hilar IgG4+ staining was significantly associated with the presence of dominant biliary strictures (P = 0.01) and need for biliary stenting (P = 0.001). There did not, however, exist any significant differences in the age at PSC diagnosis, presence of inflammatory bowel disease or extrahepatic autoimmune disease, frequency of cholangiocarcinoma, interval between diagnosis and transplantation, or post-transplant PSC recurrence or survival. Of 51 control liver sections (PBC = 18; HCV = 19; HBV = 8; AIH = 6), none had marked or moderate hilar IgG4+ staining, whereas mild staining was seen in only 10% (P < 0.001). Marked (>50/HPF) hilar IgG4+ lymphoplasmacytic infiltration is frequently observed in PSC and associated with the presence of dominant biliary strictures. However, unlike serum IgG4+, this does not seemingly associate with clinical disease course.
Highlights
Bateman 2012) and sits within a broader family of IgG4related systemic disease of which autoimmune pancreatitis (AIP) is the commonest manifestation (Stone et al 2012)
Marked hilar lymphoplasmacytic infiltration was significantly associated with marked hilar IgG4+ staining (P < 0.001)
Of 51 control liver sections (PBC = 18; HCV = 19; HBV = 8; autoimmune hepatitis (AIH) = 6), none had marked or moderate hilar IgG4+ staining, whereas mild staining was seen in only 10% (P < 0.001)
Summary
Bateman 2012) and sits within a broader family of IgG4related systemic disease of which autoimmune pancreatitis (AIP) is the commonest manifestation (Stone et al 2012). An international consensus group recently published their diagnostic criteria for IAC incorporating similar histological, radiological, serological and clinical findings to those found in the Mayo Clinic’s HISORt criteria for AIP (Chari 2007; Ohara et al 2012). Two key diagnostic features of IAC are an elevated serum IgG4 level and the presence of tissue-infiltrating IgG4-positive plasma cells on biopsy. Tissue-infiltrating IgG4-positive plasma cell deposition has been reported in PSC liver, and in some studies, this has been proposed to signify a more aggressive clinical course with shorter time to transplantation and a higher likelihood of disease recurrence (Zhang et al 2010). No study has assessed the significance of finding liver-infiltrating IgG4+ plasma cells in PSC using the latter cut-off
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