Long-Term Follow-Up of Active Treatment Versus Minimization of Immunosuppressive Agents in Patients With BK Virus-Associated Nephropathy After Kidney Transplant.

Objectives: There is no active treatment for postrenal transplant BK virus-associated nephropathy proven to be effective so far. We assessed the effectiveness of actively treating this condition with combined leflunomide, intravenous immunoglobulin, and ciprofloxacin on long-term graft outcome compared with minimization of immunosuppressive drugs. Materials and Methods: Kidney transplant recipients were screened for BK virus-associated nephropathy. Group 1 comprised 22 kidney trans plant recipients with twice-positive BK virus polymerase chain reaction results in urine and blood. After diagnosis was confirmed with graft biopsy, antimetabolite (mycophenolate mofetil or azathioprine) was changed to leflunomide and intravenous immunoglobulin and oral ciprofloxacin were given. Group 2 comprised 33 BK virus-associated nephropathy patients treated conventionally with reduced immunosuppressive medications. Results: Fifty-five patients were treated (38 males [69%], 28 patients [50.9%] with type 2 diabetes mellitus). Mean HLA antigen mismatches were 3.65, and 28 patients (50.9%) were HLA-Cw7 negative. All patients received induction therapy, 30 patients (55.6%) received thymoglobulin, and 29 patients (52.7%) received antirejection therapy before BK virus-associated nephropathy diagnosis. Maintenance immunosuppression was prednisolone in 53 patients (96.3%), mycophenolate mofetil (2 g daily) in 52 patients (94.5%), and tacrolimus in 28 patients (50.9%). Subsequent rejection episodes occurred in 38% of patients after diagnosis. Basal mean estimated glomerular filtration rate was 52.5 +/- 25.5, which was reduced significantly to 38.1 +/- 27.8 mL/min/1.73 m(2) (P < .0001) at end of study but without significant differences between the groups (P = .08 and P = .17). Follow-up was 7.3 +/- 4.99 years. Although no significant differences were shown in patient outcome, graft survival was significantly better in group 2 (P = .032). Conclusions: Administration of 3 different anti-BK virus agents (leflunomide, intravenous immuno globulin, ciprofloxacin) added no benefit to long-term outcome in patients with BK virus-associated nephropathy. Reduction of immunosuppressive medications appears to be a more effective treatment.