granzyme b level in acute renal transplant rejection

introduction: acute rejection of renal transplant is a serious and common systemic inflammatory disorder which leads to decreasing half-life of transplant organ. current diagnoses method is an invasive biopsy procedure on allogtraft kidney. therefore, applying a novel and noninvasive diagnostic method such as granzym b level in acute renal transplantation could help patients and improves survival of transplanted tissue. materials and methods: this study was an analytical descriptive one in which 32 patients, who underwent kidney transplantation from may to august 2003 in uremia - iran were studied. five sequential blood samples from each patient between day 2 and day 20 after renal transplantation were obtained continuously. serum levels of granzyme b were measured using immunoassay method. in addition, in case of uncertain acute rejection, needle biopsies of kidney were performed. patients were followed up to 9 - 12 months to control function of transplanted tissue. results: it was shown that 13 patients (40.5 %) with mean age of 33 years and 18 months duration of hemodialysis showed stable function of transplanted tissue. the mean serum levels of granzyme b in these patients were 148 + unit/ml. 19 patients (59.9 %), mean age of 43.74 years and mean hemodialysis duration 27 months, showed unstable function of transplanted tissue.  6 patients (19%) showed acute transplant rejection and 13 patients showed other etiological reaction. the mean serum levels of granzyme b in acute rejection in the first sample was 250.20 + 46.25 units/ml (day 2-5) in the second sample was 286.50 + 49.92 units/m (day 6-8), in the third sample was 275.60 + 68.40 units/ml (day 9-11) and in the forth sample was 253.17 + 86.14 units/ml (day 12-16). in relation to other two groups, the difference was statistically significant (p< 0.05). the mean serum levels of granzyme b in acute rejection group, in the fifth sample was 158.17 + 29 units/ml (day 17-20), and there was no statistical significant difference between two groups. conclusion: the study confirmed that continuous measurement of granzyme b   in whole blood by immunoassay methods within three weeks after renal transplantation could be a rapid and noninvasive diagnostic method for renal transplant rejection evaluation. significant decrease of granzyme b at the end of third week after transplantation and after treatment with anti-acute rejection medicines could be helpful to evaluate response to anti-rejection treatment of transplantation. in conclusions, measurement granzyme b offers a noninvasive diagnosing acute rejection of renal allografts.