Objective: Patients with primary sclerosing cholangitis (PSC) and elevated immunoglobulin (Ig) G4 have been shown to have more severe disease with a shorter time to orthotopic liver transplantation (OLT). The aim of the study was to investigate the clinical outcomes of PSC and UC in patients with elevated serum IgG4.

Methods: We analyzed data from 50 patients with PSC and known serum levels of IgG4. They were divided into groups called high IgG4 (>112 IU/L; n = 10) or normal IgG4 (n = 40). We compared the requirement of OLT and colectomy between groups.

Results: High IgG4 was found in 10 PSC patients (20%). UC was associated in 9/10 patients with high IgG4 vs. 32/40 patients with normal IgG4 (p=0.67). Patients with high IgG4 were younger at PSC diagnosis (28.1 ± 13.9 vs. 37.6 ± 13.4 years, P=0.04), more likely to have backwash ileitis (7/9 vs. 12/32, P < 0.001) and UC flares (median of 5.5 vs. 1.5, P = 0.02). Kaplan-Meier curve analysis showed that patients with elevated IgG4 had reduced colectomy-free survival than patients with normal IgG4 (Log Rank p < 0.001). The median time to colectomy was 5 years from UC diagnosis in high IgG4 group vs. 12 years in the normal IgG4 group (p = 0.01).

Conclusions: Elevated IgG4 was seen in a small number of PSC patients. Most of these patients had associated UC, were younger at the time of PSC diagnosis, more likely to have backwash ileitis and had reduced colectomy-free survival than patients with normal IgG4.