Seronegative atypical anti-glomerular basement membrane crescentic glomerulonephritis

Area of Science:

• Nephrology
• Immunology
• Pathology

Background:

• Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune condition typically characterized by circulating antibodies against the GBM.
• Diagnosis is often confirmed by serological tests and kidney biopsy findings.

Observation:

• A 46-year-old female presented with fatigue, hematuria, fluid overload, and acute kidney injury (creatinine 10.8 mg/dL).
• Initial serologies for antinuclear antibody (ANA), anti-neutrophilic cytoplasmic antibody (ANCA), and anti-GBM antibody were negative.
• Renal biopsy showed significant glomerular crescent formation (90%) and linear IgG deposition on immunofluorescence.

Findings:

• Despite negative serologies, the kidney biopsy findings were diagnostic of anti-GBM disease.
• Treatment with steroids and cyclophosphamide was initiated but discontinued due to infectious complications.

Implications:

• This case underscores the importance of considering atypical anti-GBM disease in patients with compatible biopsy findings, even with negative serological results.
• Standard commercial assays may not detect all forms of anti-GBM antibodies, necessitating a high index of suspicion and reliance on biopsy evidence.