Abstract: TH-PO1100
Anti-Brush Border Antibody Disease (ABBA): Two Case Reports
Session Information
- Pathology and Lab Medicine
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1700 Pathology and Lab Medicine
Authors
- Alzghoul, Husam Mohammad, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
- Obeidat, Mohammad, Arkana Laboratories, Little Rock, Arkansas, United States
Introduction
ABBA is an autoimmune tubulointerstitial kidney disease that primarily affects older individuals and results in progressive kidney failure. associated with autoantibodies against the proximal tubular brush borders. ABBA often occurs with other kidney diseases and diagnosis requires the presence of tubular injury with Deposition of IgG along tubular basement membranes (TBMs), proximal tubular brush borders, Bowman’s capsule, and/or glomerular basement membranes(GBMs).
Case Description
We are reporting two cases, The first case for a 71-year-old female with a history of diabetes mellitus, hypertension, and chronic kidney disease (CKD), who presented with acute kidney injury. Workup revealed a rise in serum creatinine from 1.6 to 6.46 mg/dL with proteinuria (UPCR 1.15 g/g). Immunofluorescence (IF) Showed 3+ granular staining for IgG in GBMs and TBMs. Positive staining for both LRP2 and Cubilin. The second case for a 70-year-old male with a history of hypertension, CKD. Presented for CKD evaluation. Creatinine was 2.34 mg/dL with 3+ hematuria on urinalysis and proteinuria (UPCR 0.5 g/g). IF demonstrated 3+ granular staining along the TBMs for IgG , TBM is positive for Cubilin and negative for LRP2 staining. EM showed TBM electron dense deposits in both cases.
Discussion
Age and coexisting glomerular diseases may contribute to underrecognition of ABBA, potentially leading to undertreatment. Emerging data suggest that combination therapy with corticosteroids and other immunosuppressants results in partial or complete remission in 73.3% of patients.The histopathologic spectrum of ABBA and its overlap with tubulointerstitial features of other kidney diseases highlight the importance of additional staining. As shown in the second case, where LRP2 was negative despite being reported as positive in most cases.
-A&C In Case 1
-B&D In Case 2
-star; normal stain for LRP2/cubilin, brush border
-white arrow; abnormal TBM stain for cubilin
-blue arrow; the absence of TBM stain for LRP2
-F In Case 1, both LRP2 and cubilin show abnormal TBM stain
-E In Case 2, LRP2 negative; cubilin positive along TBMs.