Abstract: TH-PO461
NELL1 Renal Biopsy Antigen Staining of Membranous Nephropathy Preceded Clinical Lymphoma Recurrence
Session Information
- Glomerular Diseases: Podocytopathies and Nephrotic Syndromes
November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1302 Glomerular Diseases: Immunology and Inflammation
Authors
- Khan, Ayesha Anwar, Mayo Clinic, Jacksonville, Florida, United States
- Albadri, Sam, Mayo Clinic, Jacksonville, Florida, United States
- Aslam, Nabeel, Mayo Clinic, Jacksonville, Florida, United States
- Mao, Michael A., Mayo Clinic, Jacksonville, Florida, United States
Introduction
Membranous nephropathy (MN) is the most common cause of nondiabetic nephrotic syndrome (NS) in Caucasian adults. New MN associated antigens with clinicopathological relevance have been discovered. NELL1 antigen has a reported prevalence of 16% in PLA2R- or THSD7A-negative patients.
Case Description
A 70-year-old Caucasian male with history of primary GI follicular lymphoma diagnosed in 2015 and CLL presented for evaluation of nephrotic syndrome. Following Rituximab for one year, remission was declared with negative endoscopies with biopsies and inactive PET scan. Creatinine was 1.27 mg/dL, urine microscopy showed WBC 14/HPF and RBC 4/HPF, and a 24-hour urine revealed 12.9 g protein and measured CrCl 94.2 ml/min. Noninvasive work-up included negative hepatitis B, C, HIV, antiphospholipase A2 receptor, ANCA, ANA, and complement C3 and C4. Serum monoclonal protein study was positive, however serum free light chains and UPEP were normal.
Renal biopsy was performed. Light microscopy showe immune complex membranous nephropathy with immunofluorescence showing 2-3+ granular capillary IgG and C3 staining with equal kappa/lambda staining. Immunohistochemistry was performed with PLA2R, THSD7A, and NELL1. NELL1 stained positive (Fig 1). After work-up for secondary etiologies, the patient was treated with Rituximab with ongoing improvement in proteinuria (24-hour urine protein 648 mg after one year).
Discussion
This case of NELL1-associated membranous nephropathy associated with lymphoma highlights the clinical utility of renal biopsy antigen staining for diagnosis and management. The onset of NS secondary to membranous nephropathy can occur at different stages in malignancies. It is possible that this NELL1-associated MN may precede clinically detectable underlying malignancy. Studies have proposed monitoring serologic NELL1 antibodies to aid management of progression, recurrence, or remission of the disease.
(b)IHC stain NELL-1