Monocytes and human renal glomerular disease: a quantitative evaluation.

Human renal biopsies (n = 177) were quantitatively evaluated by histochemical means (alpha-naphthyl acetate for nonspecific esterase) for the presence of monocytes within glomerular tufts (excluding crescents). The number of monocytes per glomerulus was counted to obtain the nonspecific esterase index. Histologic, electron microscopic, and direct immunofluorescent features were analyzed. Cases were grouped according to whether intraglomerular electron-dense deposits were present and, if so, their predominant position. Five groups were obtained: group I, subendothelial (39 biopsies); group II, mesangial (24 biopsies); group III, subepithelial (22 biopsies); group IV, intramembranous (2 biopsies); and group V, no detectable deposits (90 biopsies). For each group, the mean nonspecific esterase index was determined: I = 2.0, II = 0.28, III = 0.26, IV = 0.08, and V = 0.13. Group I was subdivided on the basis of whether extensive mesangiocapillary change was present or not. The mean nonspecific esterase index for the group I biopsies without mesangiocapillary change was 2.5, which was significantly higher than the scores for biopsies with mesangiocapillary change (0.2) and those from the other groups (p < 0.01). The results indicate an association between relatively high levels of intraglomerular monocytic infiltration and diseases characterized by having electron-dense immune deposits predominantly in the subendothelial position without extensive mesangiocapillary change. Diseases with predominantly subepithelial, mesangial, intramembranous, or no detectable deposits generally showed low numbers of intraglomerular monocytes.