Monocyte involvement in glomerular crescents: a histochemical and ultrastructural study.

The biopsies from 14 patients with glomerulonephritis with crescents were studied to determine the extent of monocyte involvement in crescent formation. Antiglomerular basement membrane (GBM) disease was diagnosed in six and immune complex (IC) glomerulonephritis in eight. Alpha-Naphthyl acetate staining of frozen sections for nonspecific esterase was done in 11 cases (five anti-GBM and six IC), and the peroxidase-antiperoxidase method for lysozyme was done in two (both IC). Electron microscopy of crescents was carried out in 12 cases. The mean number of nonspecific esterase (or lysozyme-excluding neutrophils) positive cells was 6.0 (+/-5.8) in the anti-GBM cases and 1.1 (+/- 1.4) in the IC ones. The difference was significant (P less than 0.05). By electron microscopy the cellular crescents in cases of anti-GBM disease contained variable numbers of monocytes (macrophages) and epithelial cells. Those from cases of IC disease showed very few monocytes but numerous epithelial cells. The results show that monocytes participate in a numerically significant way in crescent formation in anti-GBM disease but appear to be of minor importance in crescents in IC disease.