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

摘要

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 re-cipients 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 aza-thioprine) was changed to leflunomide and intravenous immunoglobulin and oral ciprofloxacin were given. Group 2 comprised 33 BK virus-associated nephro-pathy patients treated conven-tionally 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 m2 ( 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.