GLOMERULONEPHRITIS-MONOCLONAL Ig GN SUBTYPES

SUMMARY

1. Monoclonal Ig deposition disease. Characterised by deposition of M Ig along the glomerular and tubular basement membrane. Subtypes: light-chain (most common), heavy chain (co-deposition of C3 & C1q), light & heavy chain.

2. Proliferative GN with monoclonal Ig deposits. Proliferative GN with exclusively glomerular M Ig deposits on IF and ordinary granular electron dense deposits seen on EM. Most often IgG, less commonly IgM, rarely IgA. Presentation: NS, HTN, low C3/C4, 20-30% have a detectable M protein in serum or urine.

3. Immunotactoid Glomerulopathy. Proliferative GN on LM, IgG deposits on IF, and capillary wall deposits with a microtubular structure on EM. Deposits: IgG, C3 & C1q. Can be assoc. with underlying lymphoproliferative disorder.

4. Fibrillary Glomerulonephritis. Characterised by glomerular deposition of non-amyloid fibrils. Mesangial proliferative GN most common pattern (70%), followed by membranoproliferative GN, endocapillary proliferative GN and diffuse sclerosing GN. Deposits: IgG in all patients with C3, IgA and IgM in some patients.

Reference(s)

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