A 25-year experience with pediatric anti-glomerular basement membrane disease

Area of Science:

• Nephrology
• Pediatric Rheumatology
• Immunology

Background:

• Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune disorder characterized by autoantibodies against GBM collagen, leading to rapidly progressive glomerulonephritis (RPGN).
• Pulmonary hemorrhage can also occur, forming Goodpasture Syndrome, though its association with anti-GBM disease in children is less understood than in adults.
• Environmental factors like cigarette smoking and hydrocarbon exposure are implicated in adult anti-GBM disease, but pediatric data is limited.

Observation:

• A 25-year review of pediatric renal biopsy and autopsy specimens identified four cases of anti-GBM disease in patients under 18 years old.
• The cases presented with varying degrees of RPGN and crescentic glomerulonephritis, confirmed by linear immunoglobulin G immunofluorescence (IF).
• One autopsy case demonstrated diagnostic IF despite undetectable serum anti-GBM antibodies but positive anti-neutrophil cytoplasmic antibodies (ANCA).

Findings:

• Among the four pediatric patients, two had pulmonary manifestations.
• One adolescent reported a history of cigarette smoking, and another had probable hydrocarbon exposure.
• Serum anti-GBM antibodies were not always detectable; some patients were ANCA-positive, anti-GBM-negative, representing a unique subset.

Implications:

• Anti-GBM disease is an uncommon but significant condition in pediatrics, necessitating awareness for timely diagnosis and management.
• The findings suggest a potential, albeit incompletely understood, role for environmental exposures in pediatric anti-GBM disease.
• Diagnostic approaches may need to consider ANCA testing and acknowledge the possibility of undetectable anti-GBM antibodies in some pediatric cases.