Do antithymocyte globulin-free acute rejection therapies increase the risk of polyoma nephropathy in renal transplant recipients?

Introduction BK virus nephropathy is a serious complication that can lead to allograft kidney loss. Excessive immunosuppression increases the risk. We aimed to evaluate whether there is an increased risk of BK viremia and nephropathy in patients who underwent high-dose immunosuppression due to the development of acute rejection in the early period after kidney transplantation. Methods This retrospective cohort study was performed between April 2015 and March 2016. Twenty-nine patients who had biopsy proven acute rejection in the first three months were evaluated for BK viremia and nephropathy. Thirty patients who transplanted at the same period were the control group. Plasma BK-DNA values were examined at 1,2,3,6,9 and 12 months after the rejection treatment, and at 3,6,9 and 12 months in the control group. Presence of polyoma nephropathy was examined with surveillance biopsies at the 6. and 12. months. Results Acute rejection treatment was started on the 12th day after transplantation (2-37 days). Seventeen cellular rejections and 12 humoral rejections were reported by biopsy. Two of 12 humoral rejections were suspicious. Only pulse steroid (PS), (n=18), PS, plasmapheresis, intravenous immunoglobulin (n=8), PS, intravenous immunoglobulin (n=2) and PS, plasmapheresis (n=1) treatments were performed. In 21 patients in the rejection group and 25 patients in the control group, BK-DNA was not positive at all. Two patients had graft loss in 11 and 36 months in the rejection group. Graft losses were secondary to rejection. Conclusions Treatment with anti-thymocyte globulin-free regimens after acute rejection episodes did not lead to increase in BK viremia.