Abstract: TH-PO0764
Monotypic IgA Deposition Kidney Disease: A Large Health System Experience
Session Information
- Glomerular Histopathology: Evolving Insights
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- El Falah, Hamza, Lenox Hill Hospital, New York, New York, United States
- Ayehu, Gashu H., Long Island Jewish Medical Center, Hempstead, New York, United States
- Ziemba, Yonah C, Long Island Jewish Medical Center, Hempstead, New York, United States
- Jhaveri, Kenar D., Long Island Jewish Medical Center, Hempstead, New York, United States
- Rosenstock, Jordan L., Lenox Hill Hospital, New York, New York, United States
Background
IgA nephropathy (IgAN) is typically a polyclonal disorder. Monotypic IgA nephropathy (mIgA) with staining for only one light chain is uncommon and the prevalence unknown.
Methods
We searched the kidney biopsy database of our health system from 2009 using keywords to identify cases of monoclonal IgA deposition and charts were reviewed.
Results
We found 9 cases of mIgA out of 594 cases of IgA deposition (1.5%). Biopsies had kappa light chain restriction in 6 and lambda in 3. Histological patterns were mesangioproliferative (55.6%), sclerosing (33.3%) and membranoproliferative (11.1%). The median age was 43 and 66.7% were males, similar to the overall IgAN population (44 and 54% male). No patient had known hematological disease. Initial median serum creatinine was 1.7 mg/dL (range:1.2-3.6 mg/dL, n=8) and eGFR 41 ml/min (range: 17-66 ml/min). Baseline proteinuria by PCR was 1.7 g/g (range: 0.2-9, n=5). Serum free light chain ratio was normal in all 6 patients tested. Immunofixation was negative in 5 patients but one patient had a trace lambda paraprotein matching her biopsy light chain restriction. Bone marrow biopsy was performed in 4 patients, and was negative for neoplastic clones. Blood and bone marrow flow cytometry was available in 2 patients and was negative. Follow-up data was available in 6 patients. The median follow-up duration was 38 months (range: 7-81 months). One patient developed ESKD after 16 months. At follow-up, median creatinine was 1.67 mg/dL (range: 1.2-2.4 mg/dL), and eGFR 44 ml/min. Proteinuria was 0.5 g/g (range: 0.1-0.61 g/g). All 6 patients were treated with RAS agents; two patients were also put on endothelin antagonist.Two patients had immunosuppressive therapy. One patient with kappa restriction had both anti-plasma cell therapy and anti-B cell therapy. Another patient with lambda restriction received anti-B cell therapy and steroid course. Both patients had stable to improved renal function and improved proteinuria.
Conclusion
This study could not definitively determine whether mIgAN represents a variant of IgAN or a monoclonal gammopathy of renal significance. Except for one patient with a trace lambda paraprotein detected in the blood, there was no evidence of hematologic malignancy on blood workup (n = 6) or bone marrow biopsy (n = 4). Larger studies are warranted to better characterize this patient population.