[A case report of BK virus nephropathy after an ABO-incompatible living kidney transplantation].

We present a case of 29-year-old female who underwent an ABO-incompatible living kidney transplantation from her father. The serum creatinine (s-Cr) level of this patient was stabilized about 1.1-1.2 mg/dl during the first 3 months after the transplantation. Thereafter, the function of allograft was deteriorated gradually. A biopsy performed on post-transplant day (PTD) 520 to evaluate a rise in creatinine revealed an interstitial nephritis and chronic renal allograft nephropathy. The renal function worsened persistently, although we increased the dosage of immunosuppressant subsequently. The following biopsy performed on PTD 630 showed a suspicion of BK virus nephropathy, with a mass of tubular epithelial nuclear inclusions and an interstitial nephritis. The diagnosis of BK virus nephropathy was confirmed on the immunohistochemistry staining using anti-SV40 antibody and PCR analysis. Despite reducing the immunosuppressants, the function of the allograft worsened progressively and was lost on PTD 912.