MPO-ANCA-positive IgA nephropathy successfully treated with tonsillectomy

Area of Science:

• Nephrology
• Immunology
• Internal Medicine

Background:

• IgA nephropathy (IgAN) is a common cause of glomerulonephritis, often associated with hematuria and proteinuria.
• Myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) positivity can indicate systemic vasculitis but its role in IgAN is less understood.
• Recurrent infections, such as tonsillitis, have been implicated in IgAN flares.

Observation:

• A 20-year-old Japanese woman with IgAN presented with gross hematuria and crescents on biopsy, initially negative for MPO-ANCA.
• Despite treatment, proteinuria increased, coinciding with recurrent tonsillitis and the emergence of MPO-ANCA positivity.
• Following tonsillectomy and low-dose prednisolone, proteinuria significantly improved, creatinine clearance normalized, and MPO-ANCA became undetectable.

Findings:

• This case demonstrates a potential association between tonsillitis, IgA nephropathy activity, and MPO-ANCA production.
• Resolution of tonsillitis correlated with clinical improvement in IgAN and serological normalization of MPO-ANCA.
• The findings suggest that infections may trigger or exacerbate IgAN and influence MPO-ANCA status.

Implications:

• Tonsillectomy may be a therapeutic option for IgA nephropathy patients with concurrent tonsillitis and MPO-ANCA positivity.
• Further research is warranted to elucidate the mechanisms linking infection, IgAN, and MPO-ANCA.
• This case highlights the importance of considering infectious triggers in the management of IgA nephropathy.