Elevated immunoglobulin G4 level is associated with reduced colectomy-free survival in patients with primary sclerosing cholangitis and ulcerative colitis.
ABSTRACT BACKGROUND AND AIM: 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 (>112IU/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±13.4years, 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 5years from UC diagnosis in high IgG4 group vs. 12years 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.