[Macrophage infiltration in human glomerulonephritis: histochemical study by the non-specific esterase method]

Area of Science:

• Nephrology
• Immunopathology
• Renal Pathology

Context:

• Glomerulonephritis (GN) encompasses diverse kidney diseases.
• Assessing macrophage infiltration is crucial for understanding GN pathogenesis.
• Non-specific esterase (NSE) activity is a marker for macrophage detection.

Purpose:

• To quantify glomerular macrophage infiltration in various types of glomerulonephritis using NSE activity.
• To explore the relationship between macrophage infiltration, disease type, and glomerular deposit characteristics.

Summary:

• This study measured non-specific esterase (NSE) activity in 77 renal biopsies to detect glomerular macrophages in different forms of glomerulonephritis (GN).
• Macrophage infiltration was notably high in cryoglobulinemia-associated diffuse proliferative GN (NSE index >10).
• Lupus nephritis showed low macrophage infiltration (NSE index 0.44), while diffuse proliferative GN with extracapillary proliferation had an NSE index >1. IgA nephropathy generally showed minimal infiltration, except in extracapillary forms.
• A correlation was observed between monocytes, the quantity, and localization of glomerular deposits, with higher NSE indices linked to large sub-endothelial deposits of immunoglobulins, C3, and/or fibrin.

Impact:

• Provides quantitative insights into macrophage roles in specific glomerulonephritis subtypes.
• Highlights the potential of NSE index as a biomarker for disease activity and prognosis in GN.
• Suggests a link between macrophage infiltration and the severity of immune complex deposition in the glomerulus.