Immunoglobulin G4‐positive plasma cell infiltration in explanted livers for primary sclerosing cholangitis

Abstract

To explore whether immunoglobulin (Ig)G4-related sclerosing cholangitis (IgG4-SC) contributes to end-stage primary sclerosing cholangitis (PSC) in the United Kingdom. This study consisted of 41 patients who underwent liver transplantation for advanced PSC. Explanted livers were examined histologically with an emphasis on IgG4-positive plasma cell infiltration. Thirty-nine cases (95%) had minimal or mild infiltration of IgG4-positive plasma cells (≤ 30 cells/high-power field). In contrast, two cases (5%) showed plasma cell IgG4-positivity in more than 100 cells/high-power field. IgG4-positive plasma cells were accumulated preferentially in a (xantho)granulomatous tissue within large bile ducts. Except for the presence of IgG4-positive plasma cells, there was no significant histological difference between IgG4-positive and negative cases. Both showed sclerosing cholangitis with bile duct erosion and xanthogranulomatous reaction more in keeping with PSC than typical IgG4-SC. Clinically, the two patients differed from typical IgG4-related disease, in that both had associated ulcerative colitis, and one of them was younger than expected for IgG4-SC (28 years old). No classical IgG4-SC could be identified in patients explanted for PSC. The two cases identified with numerous IgG4-positive plasma cells suggest a superimposed immune mechanism of uncertain nature. A prospective study is needed to assess whether such cases will be steroid-sensitive.