K. Kawasaki

Urinary Excretion of Podocalyxin Indicates Glomerular Epithelial Cell Injuries in Glomerulonephritis

Immunofluorescent study of urine sediments was performed to detect glomerular epithelial cell injuries using specific monoclonal antibody against podocalyxin, a glycoprotein that is prominently expressed on glomerular epithelial cells. Three kinds of structures (casts, granules and cells) were stained in urine sediments from various glomerular diseases. The presence of podocalyxin in urines was confirmed by absorption test, immunoelectron microscopy and Western blotting. Podocalyxin was detected in the urinary sediments of patients with various forms of glomerulonephritis, particularly those with acute onset. The amount of their urinary excretion apparently indicates the degree of the glomerular epithelial cell injuries in glomerular diseases.

Origin of hyperplastic epithelial cells in idiopathic collapsing glomerulopathy

Glomerular epithelial cell hypertrophy and hyperplasia are listed as the primary criteria for the diagnosis of collapsing glomerulopathy (CG), a distinct variant of focal segmental glomerulosclerosis. However, the extent of podocyte phenotypic alterations that occur in CG, and the origin of the hyperplastic epithelial cells remain to be established.

Detailed analysis of phenotypes of macrophages infiltrating glomeruli in rat anti-Thy1 nephritis.

A phenotypic analysis of infiltrating macrophages in rat anti-Thy1 glomerulonephritis induced by monoclonal antibody (mAb) 1-22-3 was carried out using recently reported macrophage-specific mAbs. This was combined with a more detailed quantitative analysis, counting positive cells in isolated glomeruli, to obtain more information on the roles played by macrophages in glomerulonephritis. In normal glomeruli a small number of ED1- or OX-3(anti-Ia)-positive cells but almost no ED2-, TRPM-3- or Mar-3-positive cells were observed. ED1-positive cells increased from 2 h and peaked between days 3 and 7 after mAb injection. TRPM-3-positive cells increased from day 3 and peaked on day 7, later than ED1. The numbers of OX-3-positive cells changed in parallel with those of ED1-positive cells. Mar-3, which stained blood monocytes and ED2, which is an indicator oftissue-fixed resident macrophages, did not react with glomerular infiltrating macrophages. In a double staining study, about 40% of ED1- or OX-3-positive cells costained with TRPM-3 on day 3 and the percentage increased on day 7, but hardly any cells were positive for TRPM-3 alone. This results in two different phenotypes (ED1+,ED2-,OX-3+,Mar-3-, TRPM-3- and ED1+,ED2-,OX-3+,Mar-3-,TRPM-3+) of infiltrating macrophages. We conclude that in rat anti-Thy1 glomerulonephritis, monocytes/macrophages may infiltrate the mesangium, rapidly changing their phenotype (Mar-3+ to Mar-3-) and resulting in a gradual shift to TRPM-3-positive, activated macrophages.

Nephrotoxic Serum Nephritis in Nude Rats: The Role of Cell-Mediated Immunity

The role of T cell-mediated immunity in the early phase of nephrotoxic serum nephritis (NTN) was examined by transfer of pan T, CD8-positive, and CD4-positive cells. The disease was induced by transferring rabbit gamma-globulin (RGG)-sensitized T cells to nude (rnu/rnu) rats pretreated with a subnephritogenic dose (a dose insufficient to cause proteinuria) of nephrotoxic serum. Mild but abnormal proteinuria was detected, and macrophages showed significant accumulation in glomeruli. Transfer of not only RGG-sensitized CD4-positive cells but also CD8-positive cells separated by the T cell markers OX8 and OX38 using the panning method caused an increased accumulation of macrophages in isolated glomeruli. No host antibody against rabbit immunoglobulins was demonstrated either in glomeruli by immunofluorescence or sera by ELISA in the early disease phase. These findings support a pathological role of T cells in initiation of glomerular injury in NTN.

Granulocyte adhesion to nephritic glomeruli through recognition of activated C4 and C3 in immune deposits

Sections of rat kidney with bovine serum albumin nephritis were incubated either with a single component of complement or with several components in sequence and then reacted with granulocytes. The average number of granulocytes bound to a nephritic glomerulus was elevated in sections incubated with C4 or C3 and increases were most significant when C14, C142 or C1423 were incubated.