Rejection of the transplanted organ after kidney transplantation is still a major problem concerning graft survival and lifetime quality of kidney transplanted patients. In order to improve the pre transplant risk evaluation we investigated if number of interleukin (IL)-17 producing T-cells in the blood of kidney transplanted patients could predict allograft rejection. First we optimized the ELISpot assay to reliably detect IL-17. Afterwards we isolated T-cells of 50 patients before and three months after kidney transplantation and observed the clinical process for 12 months. The T-cells were stimulated by irradiated, third party PBMCs and by phythohemagglutinin (PHA) which functioned as positive control. Finally the amount of IL-17 producing T-cells was analyzed. Three months after transplantation the mean number of spots in patients with rejection was elevated after stimulation with third party PBMCs. However, differences in IL-17 producing T-cells between patients with and without rejection were non significant (mean=38, 0, mean 29, 1, p=0, 42). Before transplantation, IL-17 were almost similar between the two groups (mean with rejection=24, 26, without rejection =24, 71, p=0, 34). Interestingly we found that the alloreactivity before transplantation correlated significantly with the reaction against PHA (r=0, 5, p=0, 002) whereas three months after transplantation it did not. Furthermore, we found by trend an inverse correlation between the dose of prednisone and alloreactivity in patients with rejection at month three after transplantation (r=-0, 6, p=0, 2) In conclusion: we successfully used an ELISpot assay to detect IL-17 producing T-cells in patients undergoing transplantation. At month three after transplantation the amount of IL-17 producing T-cells may be an indicator of transplant rejection. However, the findings have to be proven by a larger study.