Clinical significance of allograft glomerulopathy

Abstract

During the period from January 1973 to December 1990, 774 renal transplantations in 698 children were performed in our renal unit. A total of 540 grafts were examined both by light and immunofluorescence microscopy at least once. Recurrent glomerulonephritis was diagnosed in 62 grafts, de novo glomerulonephritis in 68 and allograft glomerulopathy in 38 (7%). The term allograft glomerulopathy (AGP) refers to the very specific pattern of glomerular involvement unique to renal allografts and characterized by: (1) widespread reduplication of the glomerular basement membrane due to a widening of the subendothelial space associated with (2) moderate increase in mesangial matrix and (3) interposition of mesangial matrix and cells. AGP is a glomerular manifestation of chronic rejection and is almost always associated with obliterative vascular changes. In our experience it is present in 25% of long-standing grafts (more than 10 years), but may develop early in the post-transplantation period (5 cases within the first year). In 13 of 33 patients in whom early biopsies were available, a different pattern characterized by a hypercellularity and the presence of monocytes-macrophages in the mesangial areas was observed. We suggest that this hypercellular pattern might be the early stage of the disease and could be called "acute allograft glomerulopathy" as opposed to the pattern characterized by reduplication of the glomerular basement membrane which deserves the name of "chronic allograft glomerulopathy." The exact relationship between these two patterns remains to be determined. Clinicopathologic correlations showed that chronic AGP is often associated with marked proteinuria. However, in our series proteinuria was absent or minimal in 25% of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)