S1787 Steroid-refractory IgG4-Related Disease Presenting as Sclerosing Cholangitis

Abstract

Introduction: IgG4-related disease (IgG4-RD) is characterized by tumefactive infiltration of IgG4-bearing plasmablasts and other lymphocytes, along with storiform fibrosis, into one or multiple organs, with resultant organ enlargement, fibrosis, and dysfunction. Although initial reports of IgG4-RD concerned involvement of the pancreas, other organs such as the biliary tract can be involved. We present a case of steroid refractory IgG4- RD sclerosing cholangitis (IgG4-SC). Case Description/Methods: A 67-year-old man with hypertension presented with a 2-week history of unintentional weight loss, painless jaundice, and pruritus. Exam showed jaundice and scleral icterus. Laboratory revealed elevated liver tests with an obstructive pattern, with ALP, GGT, & Bilirubin of 431 U/L, 438 IU/L, 17.6mg/dL, respectively. MRCP, ERCP, and subsequent EUS demonstrated diffuse pancreatic parenchymal hypo-echogenicity, long segment strictures at the distal common bile duct with proximal duct dilation, dilated common hepatic duct, and multiple segmental intrahepatic biliary duct strictures. Biliary sphincterotomy and stent placement resolved symptoms. Biopsy of the Ampulla of Vater revealed chronic inflammation with ulceration. Further work-up uncovered an elevated serum IgG4 of 266 mg/dL with a negative ANA, SMA, AMA, and tumor markers. He was then diagnosed with IgG4-SC and completed a course of prednisone. Relapse of symptoms prompted a repeat ERCP which uncovered biliary tree pruning and irregularity, necessitating biliary stent replacement. Due to poor tolerance with rituximab infusion, he was treated with Mycophenolate Mofetil which accomplished a year of disease quiescence. Discussion: The prime gastrointestinal manifestations of IgG4-RD include type 1 Autoimmune Pancreatitis and less commonly, IgG4-SC. Management involves high dose steroids for 4 weeks with a slow taper over years to prevent permanent fibrosis. Patients are at highest risk of relapse during steroid taper or within 6 months of completion, with a relapse rate of 15-60%. Although our patient did not have the classic predictive factors of relapse, such as proximal strictures or serum IgG4 >280 mg/dL, he had a suboptimal response to steroids which prolonged his clinical course and exposed him to repeated procedures. There is still a need for further studies regarding the role for possible combination therapy (steroids & immunosuppressive therapy) to prevent relapse in high-risk individuals.