IgA腎症とループス腎炎におけるトロンボモジュリン，プロテインC，プロテインCインヒビターの血中・尿中動態およびトロンボモジュリンの糸球体内局在

Abstract

The author investigated plasma and urinary levels of thrombomodulin (TM) antigen, protein C (PC) antigen, protein C inhibitor (PCI) activity and intraglomerular localization of TM antigen in IgA nephropathy (IgA-GN) and in lupus nephritis (LN). The subjects enrolled in this study were 40 patients with IgA-GN, 20 patients with LN and 19 healthy volunteers as controls. Plasma and urinary levels of TM and PC antigen were measured by sandwich enzyme immunoassay. Plasma and urinary levels of PCI activity were expressed as inhibition activity for activated PC. Intraglomerular localization of TM antigen was detected by immunohistochemical methods using a polyclonal antibody for human TM. Plasma TM levels in the advanced stage of IgA-GN and in diffuse proliferative LN were significantly higher than those in controls. On the contrary, urinary TM levels in the advanced stage of IgA-GN and in mesangial LN were significantly lower than those in controls. In IgA-GN there were significant positive correlations between the grade of mesangial proliferation and plasma levels of TM, PC or PCI. As for intraglomerular localization of TM, in IgA-GN the staining intensity of TM on endothelial cells of glomerular tufts was decreased according to mesangial proliferation. The staining intensity of TM was higher in mesangial LN than in diffuse proliferative LN. These findings suggest that plasma TM, PC and PCI may be involved in progression of IgA-GN and that intraglomerular TM localization is influenced by the severity of glomerular lesions in IgA-GN as well as LN.