Reducing immunosuppression preserves allograft function in presumptive and definitive polyomavirus-associated nephropathy

Am J Transplant. 2010 Dec;10(12):2615-23. doi: 10.1111/j.1600-6143.2010.03310.x.

Abstract

Early detection of polyomavirus BK (BKV) viremia and reduction of immunosuppression is recommended for preventing polyomavirus-associated nephropathy (PyVAN), but systematic histological evaluations were not performed in previous studies. We routinely screen for decoy cells and, if positive, measure plasma BKV-loads. In a cohort of 203 consecutive renal transplantations performed from 2005-2008, 38 patients (19%) developed BKV-viremia and were treated with reduction of immunosuppression. Based on subsequent allograft biopsy results and peak BKV-viremia, patients were assigned to three groups: (i) definitive PyVAN (n = 13), (ii) presumptive PyVAN defined by plasma BKV-loads of ≥ 4 log(10) copies/ml (n = 17) and (iii) low BKV-viremia (n = 8). Clearance of BKV-viremia was achieved in 35/38 patients (92%) and subsequent clinical rejection occurred in 3/35 patients (8.6%), both without any difference among the groups. Patients with definitive PyVAN had higher peak plasma BKV-loads and required longer time for clearance (8.8 vs. 4.6 vs. 2.9 months; p = 0.001). However, allograft function remained stable from baseline to last follow-up at 34 months (range 18-60) in all three groups with median serum creatinine of 1.6 mg/dl, 1.6 mg/dl and 1.3 mg/dl, respectively. We conclude that screening for BKV-replication and reduction of immunosuppression is an effective strategy to preserve medium-term allograft function even in patients developing definitive PyVAN.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • BK Virus / genetics
  • BK Virus / isolation & purification*
  • Creatinine
  • Female
  • Graft Rejection
  • Humans
  • Immunosuppression*
  • Kidney Diseases / virology*
  • Kidney Transplantation / pathology
  • Male
  • Middle Aged
  • Polyomavirus Infections / virology*
  • Tumor Virus Infections / virology*
  • Viremia / virology*

Substances

  • Creatinine