Glomerular changes in a 1-year posttransplant protocol biopsy as a useful predictive indicator in ABO-incompatible kidney transplantation

[Immunology and immunosuppression in kidney transplantation. ABO and HLA incompatible kidney transplantation]

OBJECTIVES

To perform a state of the art about immunological features in renal transplantation, immunosuppressive drugs and their mechanisms of action and immunologically high risk transplantations such as ABO and HLA-incompatible transplantation.

MATERIAL AND METHODS

An exhaustive systematic review of the scientific literature was performed in the Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of the following keywords (MESH): "allogenic response; allograft; immunosuppression; ABO incompatible transplantation; donor specific antibodies; HLA incompatible; desensitization; kidney transplantation". Publications obtained were selected based on methodology, language, date of publication (last 10 years) and relevance. Prospective and retrospective studies, in English or French, review articles; meta-analysis and guidelines were selected and analyzed. This search found 4717 articles. After reading titles and abstracts, 141 were included in the text, based on their relevance.

RESULTS

The considerable step in comprehension and knowledge allogeneic response this last few years allowed a better used of immunosuppression and the discover of news immunosuppressive drugs. In the first part of this article, the allogeneic response will be described. The different classes of immunosuppressive drugs will be presented and the actual management of immunosuppression will be discussed. Eventually, the modalities and results of immunologically high-risk transplantations such as ABO and HLA incompatible transplantations will be reported.

CONCLUSIONS

The knowledge and the control of allogeneic response to allogeneic graft allowed the development of renal transplantation.

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.

Long-term outcome of ABO-incompatible renal transplantation

Based on the long-term experience with ABO-incompatible kidney transplantation, the following can be concluded: 1. Renal transplantation across ABO incompatibility is an acceptable treatment for patients with end-stage renal failure. [table: see text] 2. Long-term patient and graft survival in ABO-incompatible kidney transplantation is influenced primarily by acute rejection episodes occurring within 1 year. 3. Despite the removal of anti-ABO natural antibodies before transplantation, hyperacute rejection crises may occur in some cases. 4. Humoral rejection is the most prominent type of rejection in ABO-incompatible renal transplantation. Even though most of this rejection is controllable with anti-rejection therapy, the prognosis for a graft that undergoes humoral rejection is significantly poor. 5. The maximum IgG titers of anti-A/B antibody before transplantation may have a harmful effect on graft acceptance in ABO-incompatible kidney transplantation. 6. Renal transplantation across ABO incompatibility is principally the most significant risk factor to affect long-term allograft function in ABO-incompatible living kidney transplantation.