No Negative Impact of Serum IgG4 Levels on Clinical Outcome in 435 Patients with Primary Sclerosing Cholangitis from Japan

Background: Several studies have demonstrated that elevated serum IgG4 levels are associated with poor outcomes of primary sclerosing cholangitis (PSC), but the impact of serum IgG4 levels on PSC remains controversial. In this study, we aimed to determine prognostic factors of patients with PSC and to investigate the association between serum IgG4 levels and the clinical features and prognosis of PSC in a Japanese cohort.

Methods: We retrospectively analyzed follow-up data for 435 patients with PSC (UMIN000018438). Patients with distinct etiologies of sclerosing cholangitis including IgG4-related sclerosing cholangitis (IgG4-SC) were excluded from this study.

Results: Serum IgG4 levels were tested at the time of diagnosis in 216 of 435 patients with PSC, and were elevated in 27 patients (>134 mg/dl, 12.5%). Clinical features at diagnosis were comparable between patients with normal and elevated serum IgG4 levels, with the exception of serum albumin. The overall and liver-transplantation free survival rate was comparable between the groups. Multivariate analysis indicated that age, albumin, and bilirubin, but not IgG4, at the time of diagnosis affected PSC prognosis.

Conclusions: The current study showed that serum IgG4 levels at diagnosis do not affect PSC prognosis in a Japanese cohort that excluded patients with IgG4-SC.