P1762the Effect of Immunosuppressive Therapy on the Clinical Follow-Up of Bk Virus in Kidney Transplant Recipients

Abstract

Background and Aims BK virus nephropathy occurs in up to 10% of kidney transplant recipients and can result in graft loss. The reactivation of BK virus is largely asymptomatic, and routine surveillance especially in the first 12-24 months after transplant is necessary for early recognition and intervention. Reduced immunosuppression and antiviral treatment in the early stages may be effective in stopping BK virus replication. This study is designed to investigate the effect of management in immunosuppressive therapy on BK virus titers and graft functions in our kidney transplant group. Method A total of 370 kidney transplant recipients between the ages of 18-69 years and receiving a triple immunosuppressive therapy (Tacrolimus+Mycophenoloic Acid+Prednisolone) were included in the study. Demographic characteristics, BK virus titers, serum creatinine and immunosuppressive drug (Tacrolimus, Everolimus) levels were measured at regular intervals in the first 24 months. Among these patients 43 of them were found to have BK virus positivity. At the time of the detection of BK virus positivity, patients were divided into three groups regarding the change in the immunosuppressive protocols: Group I: Tacrolimus + Everolimus + Prednisolone, Group II: Everolimus + Prednisolone, Group III: Tacrolimus + Prednisolone. BK virus titers and graft functions of all three groups were compared with each other. SPSS 15 for Windows was used for statistical analysis. Results The mean age of the patients was 45.3 years, and the mean duration of transplantation was 16.3 months at the time of the BK virus positivity. During the follow-up, mean Tacrolimus levels were found to be in their highest value (14.1 ng/mL) in the posttransplant three months while BK virus titer reached the highest value (1.1x106 copies/ml) in the posttransplant seven to nine months. Increased creatinine values two months after BK virus positivity were strongly correlated (p = 0.02, p = 0.008, p = 0.05, p = 0.002 at 6th, 9th, 12th and 24th months, respectively). A significant decrease in BK virus titers was observed in all three groups due to reductions in immunosuppressive treatment protocol (p = 0.005, p = 0.003, p = 0.028, in groups I, II, III respectively). Conclusion Our study favors the benefits of the prospective screening for BK virus to identify early viral replication, permit intervention, and prevent progression to nephropathy or allograft loss. The best studied treatment for BK viremia and nephropathy is careful reduction of immunosuppression