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Abstract: PO1675

Collapsing FSGS from Acquired Nephrin Antibody

Session Information

Category: Glomerular Diseases

  • 1204 Podocyte Biology

Authors

  • Lai, Hsiao Ling, East Carolina University, Greenville, North Carolina, United States
  • Thayyil, Abdullah, East Carolina University, Greenville, North Carolina, United States
  • Weins, Astrid, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Keller, Keith H., Brigham and Women's Hospital, Boston, Massachusetts, United States
Introduction

Deficits in nephrin and other podocyte components are known to result in congenital nephrotic and familial FSGS syndromes. Weins et. al. recently described acquired anti-nephrin antibody localizing in glomerular podocytes of patients with minimal change disease.

Case Description

A 16 year old male referred for new onset nephrotic syndrome progressive over 2 weeks was found to have serum albumin 1.2 gm/dL, UPCR 3.1, and elevated lipids with BP 160/100 mm Hg. Hepatitis B/C, HIV, SLE screens were negative. Renal biopsy demonstrated focal collapsing lesions with diffuse podocyte effacement. Immunofluorescence showed punctate IgG, kappa and lambda light chain staining in podocytes, but no albumin. Anti-human IgG colocalized with nephrin in the granular staining. ParvoB19 and COVID-19 titers were negative. Creatinine rose from 0.65 to 1.65 and UPCR to 10.3 but improved rapidly with high dose prednisone and ACEi. Serology for circulating anti-nephrin 2 weeks into treatment was negative, consistent with previous finding that circulating antibody levels quickly drop to low or undetectable with partial clinical remission.

Discussion

This case strengthens evidence that anti-nephrin antibodies cause disruption of the slit pore diaphragm which appears to be readily responsive to immune therapy. Anti-nephrin mediated podocytopathy may present with a spectrum of glomerular histopathology, which on the background of other susceptibility factors, can lead to more severe presentations such as collapsing FSGS.

Yellow represents merge of IgG and anti-nephrin

Punctate IgG stain in podocytes