Abstract
The ultrastructural changes in the glomerulus of 28 biopsy specimens taken from 26 patients with subchronic glomerulonephritis (GN) were studied by electron microscopy. The relationship between these morphologic changes and the clinical findings, especially preceding infections and hematuria, or the immunofluorescent studies was also studied. Subchronic GN is defined by Kinoshita as a distinct entity of chronic but nonprogressive form of GN without functional insufficiency. It is divided into four types (Type I-IV) according to the severity of the glomerular lesions. The specimens, fixed in glutaraldehyde and osmium tetroxide, or osmium tetroxide alone and embed-ded in epon epoxy resin, were sectioned with glass knives on a Porter-Blum microtome. The sections were stained with uranium acetate and lead tartrate and examined with Hitachi HS-7 electron microscope. The results were as follows, (1) The common electron microscopic finding in each type of subchronic GN was the increase of mesangial matrix. The mesangial matrix increased slightly as spotty or scattered form in Type I. In. Type II to IV it increased more and became more dense and lumpy. Most of the cases with Type 11 to if revealed the increase in mesangial cells as well as focal changes of the basement membrane, such as thinning, winding, splitting or disruption. The electron dense, well defined deposits in the mesangiall area, which was assumed as immune deposits, were found in 18 out of 28 specimens. No deposit was. seen in the subepithelial or subendothelial side of the peripheral capillary basement membrane. It sug-gests that the immunologic reaction would probably occur in the mesangial area. (2) There was no paticular relationship between the deposit and microscopic hematuria, but four cases without microscopic hematuria had no deposit. (3) Seventeen cases had chronic tonsillitis at the time of admission, 13 of which showed the deposit: in the mesangium. (4) Three of 4 cases without the deposit revealed the presence of IgG and β1C-globulin in the mesan-gium by fluorescent antibody technique, but neither IgA nor IgM was demonstrated. IgA and IgM were usually found in the mesangium of the cases with the deposit. There seems to be close relationship 4 between the presence of IgA or IgM and the deposit. (5) It is assumed that a few different immunologic mechanismus may contribute to the pathogenesis of subchronic GN.
