小児IgA腎症ならびに紫斑病性腎炎における糸球体内細胞外基質成分の免疫電顕的研究

Abstract

Immunoelectron microscopic investigation for extracellular matrix (ECM) components was carried out in renal biopsy tissues from 31 children with IgA nephropathy and 22 children with Henoch-Schönlein purpura nephritis (HSPN), as well as 5 normal adults. Immunogold labeling, using antisera against Type Ⅰ, Ⅲ, Ⅳ, Ⅴ, Ⅵ collagens, laminin (Lam), fibronectin (FN), and vitronectin (VN), in normal glomeruli revealed that FN was found restrictively in mesangial matrix (MM), Lam throughout glomerular basement membrane (GBM), Type Ⅳ collagen both in MM and lamina rara interna of GBM, and Type Ⅴ collagen in podocytes in minor amounts. The immunoreactivity of Type Ⅰ, Ⅲ, Ⅵ collagens and VN was not seen in normal glomeruli. In children with mild mesangial proliferation of IgA nephropathy and HSPN, extension of FN labeling over GBM and VN distribution within mesangial electron-dense deposit (EDD)s were observed. During the progression of mesangial proliferation, the antigenic sites of Type Ⅰ, Ⅲ, Ⅴ, Ⅵ collagens and FN appeared in MM or EDDs, and the labeling intensity of Type Ⅳ collagen and FN was gradually increased in MM or GBM. In the advanced stage of sclerotic glomeruli, the distribution of Type Ⅳ collagen and Lam remained, though that of Type Ⅰ, Ⅲ, Ⅴ, Ⅵ collagens, FN, and VN was reduced. These findings suggest that ECM components such as Type Ⅰ, Ⅲ, Ⅳ collagens, FN, and VN could play an important role in MM expansion, and that the deposition of these components is closely related to the progress of glomerulosclerosis.