Impact of Subclinical Rejection on Kidney Graft Function During the First Year after Transplantation

Introduction. There is no unified opinion about the role of subclinical rejection (SR) in further kidney graft function and the necessity of its treatment. Aim of the Study. The aim of our study is to determine the impact of SR on kidney graft function during the first year after transplantation. Materials and methods. Totally 144 deceased donor kidney transplantations were performed in a single center between January 1, 2007, and March 16, 2009. The study included patients who developed the primary graft function (n=78). Protocol biopsies were performed in 28 patients. The patients were divided into 4 groups: group A - patients, who had no histological signs of rejection on their protocol biopsy; group B - patients with histological signs of rejection who were treated with steroids; group C - patients with histological signs of rejection and with no treatment; group D - patients who were not biopsied. All groups were compared for serum creatinine level, glomerular filtration rate (GFR), number of clinical rejection 1, 3, 6, 12 months after the transplantation. Results. Histological examination revealed that 18 of 28 patients who underwent the protocol biopsy had SR grade from IA to IIA (64.3%). Comparison of the group showed no statistical difference in creatinine level and GFR 12 months after the transplantation (p > 0,05 for all groups). Conclusions. During the first 12 months after transplantation SR does not significantly impact the graft function. However, the graft function was slightly worse in patients with SR and without treatment, and relatively better in patients with SR who were treated by steroids than in patients from others groups. Further follow-up is needed to determine the longer-term results.