Abstract
Background: Long-term graft loss is still a major problem in renal transplantation. The occurrence of acute rejection episodes and impaired response of the patient to anti-rejection therapy can lead to adverse graft outcome in both the short term and the long term. At present, clinical parameters and morphologic assessment of the renal biopsy serve as the basis for assessment of risk for graft failure. Objective: The goal is to establish biomarkers in renal graft biopsies, urine samples and peripheral blood that predict or detect acute rejection and stable graft conditions, and that provide information regarding prognosis. Methods: In this review, molecular markers are focused on that have been tested for the following purposes: monitoring for acute rejection; identifying steroid-resistant rejections; and monitoring for clinical transplant tolerance. Conclusion: mRNA expression patterns and markers related to inflammatory cell types and their products in graft biopsies, urine sediments and peripheral blood cells contribute to an increased sensitivity and specificity of the prediction of therapy sensitivity and long-term graft outcome. The combination of molecular analyses and cellular immunological assays is essential for undisputedly indicating presence of rejection, reversibility of the rejection by therapy, absence of rejection, long-term graft outcome, and tolerance.