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 because of 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 3 months were evaluated for BK viremia and nephropathy. Thirty patients who had transplantations 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 the 12 humoral rejections were suspicious. Only pulse steroid (PS) (n = 18); PS, plasmapheresis, and intravenous immunoglobulin (n = 8); PS and intravenous immunoglobulin (n = 2); and PS and 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 at 11 and 36 months in the rejection group. Graft losses were secondary to rejection. CONCLUSIONS: Treatment with antithymocyte globulin-free regimens after acute rejection episodes did not lead to an increase in BK viremia.