Active management of post-renal transplantation BK virus nephropathy: preliminary report.

OBJECTIVE: To assess the efficacy of leflunomide, intravenous immunoglobulins, and ciprofloxacin as active treatment of postrenal transplant BK virus nephropathy (BKVN) in graft outcome at 1 year.

PATIENTS AND METHODS: Renal transplant recipients with positive results of 2 BK virus polymerase chain reaction tests of urine and blood underwent graft biopsy to confirm BKVN. If BKVN was diagnosed, antimetabolite therapy (mycophenolate mofetil or azathioprine) was changed to leflunomide therapy accompanied by a course of immunoglobulin and oral ciproflxacin.

RESULTS: Of 18 patients evaluated, 72% were men. Nine patients received cadaveric organs, with a mean of 3.6 HLA mismatches. All patients received induction thereapy (61% thymoglobulin), and 61% received antirejection therapy before BKVN was diagnosed. Maintenance immunosuppression therapy was primarily with prednisolone (94%); mycophenolate mofetil, 2 g/d (94%); and tacrolimus (61%). At baseline, mean (SD) creatinine clearance was 35.6 (11.5) mL/min/1.73(2), which decreased to 29.3 (17.3) mL/min/1.73(2) at 1 year (P = .01). Patients were divided into 2 groups of 9 each according to creatinine clearance values. In group 1, baseline value was 44.5 (6.6) mL/min/1.73(2), compared with 25.36 (7.8) mL/min/1.73(2) in group 2, which decreased to 42.66 (12.8) mL/min/1.73(2) (P = .23) and 16.76 (9.0) mL/min/1.73(2) (P = .009), respectively, at 1 year. Three grafts (16.7%) were lost by the end of the study, all in group 2 (P = .03).

CONCLUSION: Late diagnosis and intensive immunosuppression predispose to BKVN. Early active treatment of BKVN may improve graft outcome at 1 year posttransplantation.