Review of primary sclerosing cholangitis with increased IgG4 levels

Table 2 Studies evaluating abundant tissue IgG4-positive plasma cells in primary sclerosing cholangitis patients

Ref.	Study design	Location	PSC patients’ number	Percentage (%) with abundant tissue IgG4	Key findings in PSC high IgG4
Koyabu et al[28], 2010	Case series	Japan	3	Biopsy. 2/3 (> 10/HPF)	Infiltration of IgG4-positive plasma cells in portal area of the liver. No improvement in strictures after steroid therapy.
Zhang et al[16], 2010	Retrospective cohort study with paired serum and liver explant tissue	United States	98	Liver explants. 23% (> 10 /HPF)	Shorter time to transplant. More non-cirrhotic at transplant. Higher likelihood of recurrence.
Zen et al[26], 2011	Retrospective cohort study	United Kingdom	41	29% (> 10/HPF). 5% (> 100 /HPF)	Bile duct erosion and xanthogranulomatous reaction.
Fischer et al[27], 2014	Retrospective cohort study	Canada	122	16% (> 50/HPF)	Marked hilar staining significantly associated with dominant biliary strictures and need for biliary stenting. No differences in outcome.

HPF: High power field; PSC: Primary sclerosing cholangitis.