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

Detection of glomerular macrophages in glomerulonephritis (GN) was attempted in 77 renal biopsies by measuring non-specific esterase (NSE) activity. Macrophage infiltration was at its highest in two cases of cryoglobulinemia (NSE index greater than 10) both associated with a diffuse proliferative GN. In 15 cases of lupus, macrophage infiltration was low or absent (NSE index 0.44). In diffuse proliferative GN (24 cases) only GN with extracapillary proliferation had an NSE index greater than 1. In GN with predominant IgA (23 cases), apart 2 cases of extracapillary forms, there was no notable macrophage infiltration. There is a relation between monocytes and the localization and the quantity of glomerular deposits. The NSE index is higher in the case of large sub-endothelial deposits of immunoglobulins, C3 and/or fibrin.