title: BK polyomavirus interstitial nephritis in a renal allograft recipient.
abstract: Human polyomavirus (PV) interstitial nephritis has recently been recognized as a cause of severe renal allograft dysfunction. It occurs in immunosuppressed patients after reactivation of the latent virus PV type BK (BK virus) in the renal epithelium. BK disease is defined as a morphologically manifest renal infection with cytopathic signs accompanied by varying degrees of interstitial inflammatory cell infiltrates and functional impairment. It is also identified by the presence of cells containing viral inclusion bodies (decoy cells) in the urine. The authors report a case of BK PV interstitial nephritis in a 36-year-old renal allograft recipient. Under light microscopy the chief diagnostic indicator was detection of intranuclear viral inclusions, which were found exclusively in tubular epithelial cells. Cells with viral changes were often enlarged with nuclear atypia and chromatin basophilia. Widespread interstitial plasma cell infiltrates associated with tubulitis were present. Intranuclear paracrystalline arrays of virus particles 35-38 nm in diameter were present as characteristic ultrastructural indicators. Urine samples revealed decoy cells with ground-glass-type intranuclear inclusions positive for BK virus by electron microscopy.
authors.affiliation: Department of Pathology, Chungnam National University School of Medicine, 6 Jung-gu, Munwha-1-dong, Daejeon, Korea 301-131. kssuh@cnu.ac.kr
authors.forename: Kwang-Sun
authors.initials: KS
authors.lastname: Suh
authors.forename: Suk Yeong
authors.initials: SY
authors.lastname: Kim
authors.forename: Byung Kee
authors.initials: BK
authors.lastname: Bang
authors.forename: Chul Woo
authors.initials: CW
authors.lastname: Yang
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Sung Kwon
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000328:Adult; D001739:BK Virus / Q000302:isolation & purification* / Q000648:ultrastructure; D005260:Female; D006084:Graft Rejection / Q000473:pathology / Q000821:virology; D006801:Humans; D007181:Inclusion Bodies, Viral / Q000648:ultrastructure; D016030:Kidney Transplantation; D009395:Nephritis, Interstitial / Q000473:pathology* / Q000821:virology; D027601:Polyomavirus Infections / Q000150:complications / Q000473:pathology*; D011183:Postoperative Complications; D014412:Tumor Virus Infections / Q000150:complications / Q000473:pathology*