Comparison of treatment approaches in BK virus infection in kidney transplanted patients

Backgraund: BK polyomavirus reactivation after renal transplantation is common. It is a risk factor for early allograft loss. Reducing immunosuppression is the most important approach in the treatment. The aim of this study was to investigate the efficacy of immunosuppressive therapy modification and the safety of reducing immunosuppressive therapy in patients with BKV DNA in blood and / or urine. Methods: 97 patients with BKV DNA detected in blood and / or urine followed by Istanbul Medical Faculty were included in the study. The files of the patients were retrospectively reviewed. According to the reduction of immunosuppressives, patients were divided into four groups as calcineurin inhibitor reduction, antiproliferative reduction, transition to mTORi and azathioprine. BKV DNA was measured in urine and blood before and after each treatment change. Panel reactive antibodies (PRA) were investigated before and after treatment change in all patients. Results: Of the 97 patients, 58 were male. The average age was 47 years. The mean time between transplantation and first BKV (blood or urine) was 757.01 ± 1243.29 (22-6021) days. The mean blood BKV DNA level of the first blood was found to be 27.328 copies / mL (51-448.634), and the mean urine BKV DNA level was 182.153.695 copies / mL (251-1.000.000.000). Renal biopsy was performed in 26 (26.8%) patients. BKV nephropathy was detected in 4 patients (4.1%). PRA was positive in 13 (13.4%) patients after immunosuppression was reduced. In 28 patients (29.2%) calcineurin inhibitor and in 18 patients (18.8%) antiproliferative reduced, in 10 patients (10.4%) both calcineurin inhibitor and antiproliferative reduced, 9 patients (9.4%) were switched to azathioprine as an antiproliferative drug. It was shown that blood BKV DNA level decreased significantly in patients receiving azathioprine (AZA) after the last treatment change (p value = 0.012). Conclusions: Reduction of immunosuppression is effective in the treatment of posttransplant BKV infection. However, patients should be closely monitored for newly developed PRA.