Abstract: TH-PO521
Unwanted Deposits: A Rare Cause of AA Amyloidosis
Session Information
- Trainee Case Reports - I
October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Bonakdar, Romin, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Kumar, Srikar, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Shaban, Mona, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Nickeleit, Volker, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Introduction
Amyloidosis is a disorder resulting from pathologic deposition of protein subunits in multiple organ systems, often including the kidneys. It is divided into two major subgroups: AL amyloidosis due to overproliferation of light chains from a monoclonal plasma cell population, and AA amyloidosis resulting from chronic inflammatory states including a variety of autoimmune diseases, infections, and malignancies. Identification of the associated disorder can direct therapy to minimize further organ damage. We describe a case of AA amyloidosis secondary to Castleman's disease (CD).
Case Description
A 37 year old woman with a history of anemia was referred to clinic for nephrotic-range proteinuria. Laboratory evaluation showed a urine protein:creatinine of 10.3, a serum creatinine of 0.83 mg/dL and albumin of 2 g/dL. A kidney biopsy showed glomerular amyloid deposits. Serum protein electrophoresis and serum free immunoglobulins did not show evidence of a monoclonal gammopathy. Evaluation for secondary causes of AA amyloidosis was notable for a 5 cm pararenal mass and abnormal lymph nodes on PET scan. A biopsy of the mass revealed lymph node tissue with amyloid deposits and morphologic features consistent with CD. HHV-8 and HIV testing were negative. She was started on siltuximab, a monoclonal interleukin-6 (IL-6) antibody, with reduction in her urine protein:creatinine to 2.1, improvement in albumin to 3 g/dL and an increase in her hemoglobin from 6.2 g/dL to 15.6 g/dL.
Discussion
Amyloidosis carries tremendous morbidity to affected individuals with limited, non-curative therapy available. Identification of the patient's CD as the underlying trigger of her AA amyloidosis allowed for directed treatment that resulted in dramatic improvement in her proteinuria and resolution of her anemia. Excess IL-6 is hypothesized to play a role in CD, particularly HIV and HHV-8 negative cases. This case provides additional support for the role of IL-6 inhibitors in the treatment of idiopathic CD.