Abstract: FR-PO0705
NELL-1-Associated Membranous Nephropathy Secondary to a Suspected Connective Tissue Disorder with Concurrent Immune-Mediated Thrombotic Thrombocytopenic Purpura
Session Information
- Glomerular Diseases: Membranous Nephropathy, FSGS, and Podocytopathies
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Mannam, Hari Priya Sri Sai, The University of Kansas School of Medicine, Wichita, Kansas, United States
- Chan, Wan-Chi, The University of Kansas School of Medicine, Wichita, Kansas, United States
- Kadhem, Salam, Kansas Nephrology Physicians, Wichita, Kansas, United States
Introduction
NELL-1–associated membranous nephropathy (MN) is an uncommon antigen-specific subtype linked to malignancy and autoimmune disease. Immune-mediated thrombotic thrombocytopenic purpura (TTP), caused by severe ADAMTS13 deficiency due to inhibitory autoantibodies, is a life-threatening thrombotic microangiopathy. Their coexistence is rarely described and may reflect shared systemic autoimmune dysregulation.
Case Description
A 31-year-old woman presented with progressive weakness, dyspnea, and cytopenias following streptococcal pharyngitis. Evaluation confirmed microangiopathic hemolytic anemia, thrombocytopenia, acute kidney injury, and nephrotic-range proteinuria (uPCR 5.1 g/g; albumin 2.4 g/dL). PLASMIC score was 7; ADAMTS13 activity <1% with a detectable inhibitor confirmed immune-mediated TTP. Plasma exchange achieved platelet recovery from 34000 to 104000 within 24 hours; corticosteroids and rituximab were added. Creatinine peaked at 1.6 mg/dL and normalized. Kidney biopsy showed NELL-1–positive MN without TMA features. Malignancy workup including lymph node and bone marrow biopsies was negative. Anti-RNP positivity suggested evolving connective tissue disease. Rituximab-associated serum sickness occurred and resolved. The patient was discharged with multidisciplinary follow-up.
Discussion
This case highlights the rare overlap of immune-mediated TTP and NELL-1 MN in the context of suspected systemic autoimmune disease. Severe ADAMTS13 deficiency with rapid plasma exchange response distinguishes TTP from complement-mediated TMA. Disproportionate proteinuria prompted biopsy, revealing pathologically distinct concurrent glomerular disease. NELL-1 MN without malignancy and anti-RNP positivity support a shared autoimmune pathogenesis, expanding the spectrum of NELL-1–associated disease to include evolving connective tissue disorders.
Conclusion: AKI initially attributed to TMA occurred concurrently with NELL-1–positive MN as an independent glomerular process. Anti-RNP positivity implicates an evolving connective tissue disorder as a unifying autoimmune driver. This case underscores the importance of kidney biopsy and rheumatologic evaluation in TMA patients with persistent proteinuria, as recognition of overlapping mechanisms guides multidisciplinary management and surveillance.
Acknowledgment
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