Abstract: TH-PO556
A Case of IgG4 Related Disease (IgG4-RD) Presented with Membranous Nephropathy (MGN) Several Years Before Other IgG4 Manifestations
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
- 1203 Glomerular Diseases: Clinical, Outcomes, and Trials
Authors
- Elsherbiny, Hisham, Mayo clinic, Rochester, Minnesota, United States
- Fidler, Mary E., Mayo Clinic , Rochester, Minnesota, United States
- Cornell, Lynn D., Mayo Clinic , Rochester, Minnesota, United States
- Leung, Nelson, Mayo Clinic, Rochester, Minnesota, United States
Introduction
IgG4-RD is a systemic immune mediated condition that is characterized by mass-forming inflammatory lesions and lymphoplasmacytic infiltration with increased IgG4 positive plasma cells in affected tissue. Tubulointerstitial nephritis is the most common form of renal involvement in IgG4-RD. MGN can be secondary to IgG4-RD (“IgG4-related MGN”), usually identifiable as such due to concurrent or previous other organ involvement by IgG4-RD.
Case Description
A 67 year old man initially presented with nephrotic syndrome with 7.8 g/day proteinuria. He underwent a renal biopsy which revealed by immunofluorescence global granular glomerular basement membrane staining with IgG, C3, and kappa and lambda light chains typical of MGN. The patient failed treatment with mycophenolate mofetil and subsequently was switched to oral cyclophosphamide which induced a remission. 3 Years later, at age 70, he developed chronic sinusitis that was resistant to medical treatment. At age 73, he developed bilateral large parotid glands. On further evaluation, serum IgG4 subclass was markedly elevated at 2180 mg/dL. A parotid fine needle aspiration was done which revealed a polytypic plasma cell infiltrate with increased numbers of IgG4-positive plasma cells consistent with IgG4-RD. He also underwent prostatic biopsy for enlarged prostate which revealed increased number of IgG4-positive plasma cells, consistent with involvement by IgG4-RD. The kidney disease remained in remission at the time of IgG4-RD diagnosis. Serum anti-PLA2R antibodies checked at the time of IgG4-RD diagnosis were negative.
Discussion
In this case a patient was diagnosed with IgG4-RD 7 years after initial diagnosis of MGN. PLA2R serum testing was not available at the time of initial presentation with proteinuria. The patient’s MGN could have represented primary (PLA2R-associated) MGN that was treated and was in remission; alternatively, the MGN may have represented an early manifestation of IgG4-RD, which would provide a unifying diagnosis of the immune-mediated conditions.
Teaching point: Clinicians should maintain high a suspicion for development of IgG4-RD years after initial diagnosis of MGN in the right clinical setting. Serum PLA2R testing may be contributory, as reported IgG4-related MGN cases are negative for PLA2R.