Background: There are limited published data concerning the effects of different immunosuppressive regimens on the development of polyomavirus (BKV) viremia. We examined the risk of developing BKV viremia in kidney transplant recipients receiving everolimus (EVR) or mycophenolic acid (MPA) as maintenance therapy.
Methods: We observationally analyzed 296 patients who underwent renal transplantation at our center between 2005 and 2010: 58 were treated with EVR and low-dose cyclosporine (LD-CyA) (group 1) and 238 with MPA and standard-dose CyA (group 2). All of the patients received induction therapy with basiliximab and maintenance steroids. BKV viremia (a whole-blood viral load of >850 copies/mL) was measured by means of real-time polymerase chain reaction at least once a month during a 12-month follow-up period.
Results: BKV viremia was detected in 57 patients (19%), five (9%) in group 1 and 52 (22%) in group 2. Kaplan-Meier analyses showed that freedom from BKV viremia was significantly more frequent in group 1. The mean time of onset of BKV viremia was about four months after transplantation in both groups. The median viral load was greater in group 2 (12.5 ± 6.1 vs. 2.5 ± 1.8 × 10(4) copies/mL; p = 0.01). After the onset of BKV viremia, graft function significantly declined in group 2: 11 patients developed polyomavirus-associated nephropathy (PVAN) and four presumptive PVAN; nine experienced an acute rejection after the discontinuation of MPA, and 11 (21%) lost their graft. There was no graft loss in group 1.
Conclusion: These findings suggest that in comparison with MPA and Cya, an EVR and LD-CyA regimen lowers the risk of BKV viremia after kidney transplantation and favorably alters outcomes.
Keywords: BK virus; everolimus; interstitial nephritis; kidney transplantation; mycophenolic acid; polyomavirus.
© 2013 John Wiley & Sons A/S.