Kidney Week

Abstract: FR-PO1251

Successful Treatment of ANCA-Negative Pauci-Immune Crescentic Glomerulonephritis in a Patient with Small Lymphocytic Lymphoma

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

• Cortez, Lakan S., Sutter Health, Alta Bates Summit Medical Center, Oakland, California, United States

Lakan S. Cortez, MD

• Park, Emily H., Sutter Health, Alta Bates Summit Medical Center, Oakland, California, United States

Emily H. Park, MD

• Reich, Lyndsey, Sutter Health, Alta Bates Summit Medical Center, Oakland, California, United States

Lyndsey Reich, DO, PhD

• Gilani, Hussain A., West Coast Kidney Institute, Oakland, California, United States

Hussain A. Gilani, MD

• Krijanovski, Oleg I., Sutter East Bay Medical Foundation, Oakland, California, United States

Oleg I. Krijanovski

• Weickhardt, Alexander, UCSF Health, San Francisco, California, United States

Alexander Weickhardt, MD

Introduction

Small Lymphocytic Lymphoma (SLL) and Chronic Lymphocytic Leukemia (CLL) are two related B-cell malignancies rarely associated with Pauci-immune crescentic glomerulonephritis (PIGN) usually in the setting of ANCA-positive ANCA associated vasculitis (AAV). While ANCA-negative AAV have been documented in CLL, none are seen on SLL. Literature was also limited in guiding treatment of ANCA-negative PIGN in a patient with SLL.

Case Description

An 81-year-old man with chronic untreated stage IV-A SLL and multiple cardiovascular history presented with nausea, weakness, and a 13kg weight loss over three months. He developed microhematuria 8 weeks later, and creatinine rose from 1.3 to 4.69 mg/dL, requiring hospitalization and hemodialysis. Serologic evaluation, including ANCA, was negative. Kidney biopsy revealed focal crescentic PIGN with atypical lymphoid infiltrate suggesting SLL causing paraneoplastic AAV. He was initially given pulse dose corticosteroids, Venetoclax, and Rituximab. The steroids were tapered after a month and switched to Avacopan to decrease infection risk. Gradual renal recovery was achieved, and dialysis was discontinued after three months of treatment. Patient continues to recieve maintenance Avacopan, Venetoclax, and Rituximab, and his creatinine stabilized at 2.07mg/dL 14 months after initial presentation.

Discussion

Evidence supports the role of complement system in ANCA-negative PIGN in patients with underlying B-cell malignancies. We propose the direct alpha-2-macroglobulin production of CD20 cells, promoting IgG hexamer formation, and aggregation, facilitates complement activation. While IgG hexamers specifically activate the classical pathway via C1q, studies also implicate alternative and lectin pathways in seronegative PIGN. Renal biopsy with proteomic analysis shows increased involvement of alternative and terminal complement pathways. The deposition of C4d and mannose-binding lectin has been associated with poorer renal outcomes. Complement activation in seronegative PIGN may be localized to renal tissues, explaining normal circulating complement levels. Rapid protein clearance contributes to minimal immune deposits on routine immunofluorescence. The effectiveness of Venetoclax, Rituximab combined with a C5a receptor antagonist, Avacopan supports complement-mediated injury as a key mechanism in SLL/CLL associated seronegative PIGN.