Comparative Study of Intravenous Immunoglobulin and Leflunomide Combination Therapy With Intravenous Immunoglobulin Single Therapy in Kidney Transplant Patients With BK Virus Infection: Single-Center Clinical Trial.

Objectives: Nephropathy due to BK virus infection is a major cause of graft dysfunction and loss. No specific treatment has been developed for the BK virus. Here, we compared the combination of intravenous immunoglobulin and leflunomide versus intravenous immunoglobulin to treat BK virus nephropathy after renal transplant.
Materials and Methods: This study was a randomized controlled clinical trial. Sixteen kidney transplant patients with BK virus infection were randomly divided into 2 groups; 1 group received intravenous immunoglobulin, and another group received leflunomide and intravenous immunoglobulin. P < .05 was considered statistically significant.
Results: Results of a polymerase chain reaction test for BK virus after 2 months of treatment were negative in 3 patients in the intravenous immunoglobulin group and in 7 patients in the intravenous immunoglobulin + leflunomide group. The amount of BK virus decreased significantly in each group, and a significant difference was observed between the 2 groups after 3 months (P = .014). The average level of creatinine in the intravenous immunoglobulin group at 1, 2, and 3 months after treatment was 1.7 ± 0.23, 1.8 ± 0.5, and 1.5 ± 0.3, respectively, and in the intravenous immunoglobulin + leflunomide group was 2.1 ± 0.75, 1.76 ± 0.37, and 1.4 ± 0.18, respectively (P > .05).
Conclusions: Although BK viral load decreased significantly in both groups, there was a significant difference between patients who received intravenous immunoglobulin versus those who received the combination of intravenous immunoglobulin + leflunomide after 3 months. The addition of leflunomide to the intravenous immunoglobulin treatment seems to have a better effect in reducing BK viral load. However, further studies with a larger sample and longer duration are needed.