An ultrastructural study of the membranoproliferative variant of transplant glomerulopathy

In this study we analyzed the ultrastructural features of the membranoproliferative variant of transplant glomerulopathy in 6 patients from a group of 64 renal transplant recipients who had evidenced graft dysfunction and histological diagnosis of chronic allograft rejection. The principle changes observed by electron microscopy were thickening of glomerular basement membranes by polymorphous changes that included widening of the lamina rara interna by an electron lucent material resembling plasma constituents, replication of lamina densa-like material, and inclusion of microfilaments, membranous profiles, and other cellular remnants. Proliferation of endothelial cells was a prominent finding, suggesting that a reparative endothelial response to injury may be significant to the pathogenesis of this form of transplant glomerulopathy.