The distribution pattern of extracellular matrix (ECM) components in transp
lant glomerulopathy was studied in relation to light microscopic features,
actin expression of mesangial cells, and intraglomerular inflammatory cells
. Nine cases of mild (group I) and nine cases of severe (group II) transpla
nt glomerulopathy were stained with antisera against fibronectin (FN), tena
scin (TN), collagen types III and IV, smooth muscle actin, CD45RO, CD68, an
d Ki-67 antigen. The composition of ECM was similar in the two groups. The
expanded mesangium was diffusely stained by type-IV collagen, FN and TN, an
d focally and weakly stained by type-III collagen and smooth muscle actin.
Type-IV collagen was linearly stained along the capillary walls, imparting
a double-contour feature, whereas FN and TN showed granular staining along
the capillary walls. CD68 positive cells were increased in severe transplan
t glomerulopathy, but this increase was not related to ECM deposition. Thes
e findings suggest that increased glomerular deposition of normal and abnor
mal ECM components participate in the evolution of transplant glomerulopath
y.