Educational Case: Renal allograft rejection.

Chronic rejection, the slowest presenting form of transplant rejection, typically manifests in the timespan of months to years. The pathogenesis of chronic rejection involves either cell- or humoral-mediated processes that involve memory cells, plasma cells, and antibody production against donor antigens. The findings of chronic rejection are nonspecific and include interstitial fibrosis and tubular atrophy with associated interstitial inflammation, vascular changes characterized by thickened intima containing macrophages and lymphocytes, and transplant glomerulopathy with mesangial matrix expansion and double contour of capillary walls.9 .