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Abstract: TH-PO463

Successful Remission of Exostosin-2 Positive Membranous Nephropathy Associated With Autoimmune Hepatitis With Azathioprine and Steroids

Session Information

Category: Glomerular Diseases

  • 1302 Glomerular Diseases: Immunology and Inflammation

Authors

  • Hassanein, Mohamed, University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Tio, Maria Clarissa, University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Syed, Bushra, University of Mississippi Medical Center, Jackson, Mississippi, United States
Introduction

Membranous Nephropathy (MN) is an autoimmune disease characterized by immune complex deposition in the glomerular basement membrane (GBM). Recently, Exostosin-1 and 2 (EXT1/EXT2) were reported as target antigens of the GBM especially in patients with autoimmune diseases, particularly lupus. We report a case of EXT2-positive MN associated with autoimmune hepatitis that was successfully treated with azathioprine (AZA) and steroids.

Case Description

A 46-year-old female with a history of hypertension, prediabetes, obesity, thrombotic thrombocytopenic purpura (treated with plasmapheresis, steroids and rituximab) and newly diagnosed biopsy-proven autoimmune hepatitis (on AZA) was referred to the nephrology clinic for hematuria and proteinuria. Labs showed intact kidney function with a creatinine 0.5 mg/dL, mild transaminitis and positive anti-nuclear antibodies (ANA). Urine studies showed 3-5 red blood cells per high power field and a urine protein: creatinine ratio of 1.2 g/g (normal <0.2 g/g). A complete serological workup including viral hepatitis, human immunodeficiency virus (HIV), anti-double stranded (DS) DNA antibodies, phospholipase A-2 Receptor (PLA2R) antibodies, and monoclonals were all unremarkable. Kidney biopsy showed EXT2-positive MN with background acute tubular injury and minimal interstitial fibrosis and tubular atrophy. She was started on losartan and prednisone taper with plan to transition from AZA to mycophenolate. Due to insurance related problems, she was unable to transition to mycophenolate. She was continued on AZA, losartan and steroids and went into complete remission 2 months later with a UPCR of 0.18 g/g.

Discussion

EXT-associated MN has been strongly linked to autoimmune diseases, particularly lupus. EXT positivity is thought to confer a better prognosis with lower progression to kidney failure compared to EXT-negative MN. Although our patient was positive for ANA and had no history or signs of lupus, patients with EXT-positive MN are thought to be more prone to develop lupus later in life. Treatment is controversial, including rituximab, cyclophosphamide, and steroids. To the best of our knowledge, this is the first case of EXT-positive MN associated with autoimmune hepatitis treated with AZA and steroids.