Fig. 1.

(A) Analysis of IFN-γ–induced STAT1 phosphorylation in leukocytes by flow cytometry. IFN-γ (10 ng/mL) increased p-STAT1 in healthy controls but did not increase p-STAT1 in patient. Recombinant human IFN-γ was added to Jurkat cells inoculated with serum. After cells were permeabilized, anti-pSTAT1 antibodies were conjugated, and cells were subsequently analysed by flow cytometry, revealing that anti–IFN-γ autoantibodies worked as neutralizing antibodies in this patient. (B) MRCP showing intrahepatic bile duct dilation (white arrow). (C) Endoscopic retrograde cholangiopancreatography showing hilar bile duct stricture (black arrow). IFN-γ, interferon gamma; MRCP, magnetic resonance cholangiopancreatography; p-STAT1, phosphorylated signal transducer and activator of transcription 1; STAT1, signal transducer and activator of transcription 1.