Kidney Week

Abstract: FR-PO1254

A Rare Case of Immunotactoid Glomerulopathy Associated with Lymphoma and T-Cell Large Granular Lymphocytic Leukemia

Session Information

• Onconephrology: Diagnostic Dilemmas, Therapy-Related Toxicities, and Clinical Cases
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Onconephrology

• 1600 Onconephrology

Authors

• Au, Wing Han Christy, Pamela Youde Nethersole Eastern Hospital, Department of Medicine, Hong Kong, Hong Kong

Wing Han Christy Au, MBBS

• El-Zaatari, Ziad M., Houston Methodist Hospital, Department of Pathology and Genomic Medicine, Houston, Texas, United States

Ziad M. El-Zaatari

• Leung, Nelson, Mayo Clinic Division of Nephrology and Hypertension, Rochester, Minnesota, United States

Nelson Leung, MD

• Pasvolsky, Oren, MD Anderson Cancer Centre, Department of Lymphoma-Myeloma, Houston, Texas, United States

Oren Pasvolsky, MD

• Nasr, Samih H., Mayo Clinic Minnesota Department of Laboratory Medicine and Pathology, Rochester, Minnesota, United States

Samih H. Nasr, MD

• Abudayyeh, Ala, MD Anderson Cancer Centre, Section of Nephrology, Houston, Texas, United States

Ala Abudayyeh, MD

Introduction

Immunotactoid glomerulopathy (ITG) is a rare glomerular disease, commonly associated with hematological malignancies such as lymphoplasmacytic lymphoma and multiple myeloma. We report a case of monoclonal IgG3 heavy chain ITG associated with lymphoplasmacytic lymphoma (LPL) and subsequent diagnosis of T-large granular lymphocytic (T-LGL) leukemia.

Case Description

A 74-year-old Hispanic lady presented with anasarca. Her serum creatinine was 1.03mg/dL and 24-hour urine protein was 3.1g. She had leukopenia and thrombocytopenia. Serum free κ, λ were both elevated to 77.7 mg/L and 61.1mg/L respectively, κ / λ was 1.27. Autoimmune screenings, C3 and C4 were normal. Serum immunofixation detected an IgGκ monoclonal band but urine immunofixation was negative. Kidney biopsy was performed. Light microscopy showed glomerulopathy with a predominant membranous glomerulonephritis pattern of injury. On immunofluorescence, there was bright mesangial and glomerular capillary wall staining for IgG, C3, and C1q, without staining for κ or λ. IgG subclass staining showed bright glomerular staining for IgG3 only. Congo red and DNAJB9 stains were negative. Electron microscopy revealed glomerular organized deposits characterized by small microtubules with ill-defined hollow cores. Glomerular laser microdissection followed by mass spectrometry showed large spectra for IgG3 constant region without DNAJB9, κ, λ or amyloid proteomic signature. Bone marrow exam unveiled LPL and loss of immunoglobulin light chain consistent with heavy chain disease. Patient received 2 cycles of rituximab, cyclophosphamide and dexamethasone but her creatinine increased to 3.21mg/dL and thereafter rituximab was switched to daratumumab. After 5 months of treatment, repeat bone marrow exam showed (T-LGL) leukemia and no aberrant plasma cells from the original LPL clone. Total 3 cycles of daratumumab-based chemotherapy were given but terminated due to heart failure. Amyloid heart was ruled out by endocardial biopsy. Patient’s creatinine and 24-hour urine protein improved to nadir of 1.08mg/dL and 1.7g respectively. Free κ chains improved from 100mg/L to 20mg/L and stayed stable.

Discussion

This is a unique case of heavy chain (gamma-3) ITG. Patient had suboptimal renal response to B-cell directed therapy. However, she was able to achieve partial renal and hematological responses with plasma-cell targeted therapy.