Proliferative glomerulonephritis with unusual microlamellar organized deposits related to monoclonal immunoglobulin G3 (IgG3) kappa
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A 71-year-old woman presented with massive proteinuria and microhematuria. Renal biopsy showed diffuse global membranoproliferative and endocapillary proliferative lesions with leukocytic infiltration and an irregular duplication of the glomerular basement membrane on light microscopy. Immunofluorescence study showed granular deposits of monoclonal immunoglobulin G3 (IgG3) kappa, C3, and C1q in the glomeruli. Electron microscopy revealed unique structurally organized microlamellar electron-dense deposits. There was no evidence of systemic diseases such as paraproteinemia, cryoglobulinemia, or systemic lupus erythematosus. Following renal biopsy, the oral administration of mizoribine in addition to predonisolone gradually improved the patient’s clinical status. So far, partial remission has continued for a year, and she has not been affected with hematopoietic or lymphoproliferative disorders. We report a case of proliferative glomerulonephritis with unusual microlamellar organized deposits related to monoclonal IgG3 kappa. Our case was immunologically identical to proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID). Therefore, we concluded that our case should be categorized as an atypical form of PGNMID, though it was difficult to diagnose using the usual diagnostic approach to glomerular diseases with organized deposits.
KeywordsProliferative glomerulonephritis Monoclonal IgG subclass restriction IgG3 kappa Microlamellar organized electron dense deposits
We thank Dr. Masakazu Akashi (Department of Nephrology, Kita-Asaka station clinic, Saitama, Japan) for helpful comments and Ms. Arimi Ishikawa (Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan) for expert technical assistance.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
Human and animal rights
All procedures performed in this case report were in accordance with the ethical standards of the institutional committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. This study does not contain any studies with animals performed by any of the authors.
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