Estimation of damaged tubular epithelium in renal allografts by determination of vimentin expression

Background: Various invasive and non-invasive methods have been investigated for their prognostic value in predicting the outcome of renal allografts. In the present study, vimentin expression in tubular epithelial cells (TEC) was determined by the immunohistochemical examination of biopsy specimens and the prognostic value of this method was assessed. Methods: Ninety-two renal transplant recipients were recruited for the present study. Protocol biopsy of the renal graft was performed 1, 3 and 5 years after transplantation in each case. All biopsy specimens were treated with conventional stains and immunostained with an antivimentin antibody. The correlation between vimentin expression and glomerular filtration rate (GFR) and the association between vimentin expression and histopathological findings were determined. Results: Vimentin was localized in TEC adjacent to interstitial lesions with lymphocyte infiltration and also in TEC with tubulitis or in atrophic tubules. Vimentin positivity significantly correlated with GFR and both vimentin positivity and GFR were significantly associated with the extent of chronic allograft nephropathy, but not with acute rejection. Additionally, vimentin expression and GFR 3 and 5 years after transplantation were higher in cases where graft loss occurred between 5 and 7 years after transplantation compared with graft survival cases. Conclusions: These results suggest that immunohistochemistry using antivimentin antibodies on protocol biopsy specimens is useful for the detection of injured TEC and as a predictor of allograft outcome.