Antibrush Border Antibody Disease: A Case Series

Area of Science:

• Nephrology
• Immunology
• Pathology

Background:

• Antibrush border antibody (ABBA) disease is a rare kidney condition.
• It involves immune complex deposition in proximal tubules and autoantibodies against brush border antigens like LRP2, cubilin, and amnionless.
• This leads to progressive renal tubular injury.

Observation:

• Nine patients with ABBA disease were studied across two academic centers.
• All presented with acute kidney injury and proteinuria.
• Pathology revealed immune complex deposition in proximal tubular basement membranes, with most also showing glomerular immune deposits.

Findings:

• Two of three patients treated with rituximab showed stabilized kidney function, one with concurrent mantle cell lymphoma.
• One patient with lung cancer improved after malignancy treatment.
• The remaining patients progressed to end-stage kidney disease despite conservative or glucocorticoid therapy.

Implications:

• ABBA disease generally has a poor prognosis.
• Anti-B cell therapy (like rituximab) may stabilize kidney function in some cases.
• Treating associated malignancies can also benefit patients with ABBA disease.