By ELISA, 57/244 (23.4%) of PSC patients [51/222 (23.0%) PSC, 6/22 (27.3%) AIH-PSC] were positive for PR3-ANCA compared to 6/254 (2.7%) of controls (p<0.0001) [AIH 5/65 (7.7%), AIH-PBC 0/10, PBC 0/81, HCV 0/18, HBV 0/32, healthy controls 1/48 (2.1%)]. This evidence concerns the gene PRTN3 and autoimmune hepatitis.