ESPN 50th Annual Meeting

ESPN 2017


 
Epidemiology and Morbidity of BK Polyomavirus (BKPyV) Replication and BKPyV-associated Nephropathy (BKPyVAN) in European Pediatric Kidney Allograft Recipients: Analysis of the CERTAIN Registry
BRITTA HÖCKER 1 LUKAS SCHNEBLE 1 LARS PAPE 2 PAUL SCHNITZLER 2 LUISA MURER 2 BIRGITTA KRANZ 2 LUCA DELLO STROLOGO 2 NIKOLETA PRINTZA 2 KRISTINA HEINDL-RUSAI 2 ALEXANDER FICHTNER 1 KAI KRUPKA 1 LENNART KÖSTER 1 MEMBERS OF THE CERTAIN RESEARCH NETWORK 2 HANS H. HIRSCH 2 BURKHARD TÖNSHOFF 1

1- UNIVERSITY CHILDREN^S HOSPITAL, HEIDELBERG, GERMANY
2- CERTAIN RESEARCH NETWORK
 
Introduction:

BK polyomavirus-associated nephropathy (BKPyVAN) constitutes a serious cause of allograft failure. In adults, BKPyV viremia occurs within weeks to months after kidney transplantation (KTx). According to international guidelines, frequent BKPyV DNA surveillance and judicious reduction of immunosuppression is therefore recommended at least during the first two years post-transplant. While numerous studies in adults are availa­ble, larger multicenter studies of BKPyV in pediatric KTx patients are scarce.

Material and methods:

As part of the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN), we investigated the prevalence and impact of BKPyV replication and BKPyVAN in a cohort of 209 pediatric RTx recipients (mean age 10.9 ± 5.5 years) in whom regular BKPyV DNA surveillance in urine and/or plasma was performed. 

Results:

In the 1st year post-transplant, 35.7% of patients developed BKPyV viruria; 24.3% exhibited a high viral load in urine (> 107copies/mL). BKPyV viremia was observed in 28.6% of recipients. 12.9% of patients developed a high plasma BKPyV viral load (> 104 copies/mL) in the 1st year post-transplant fulfilling the criteria of presumptive BKPyVAN. Biopsy (Bx)-proven BKPyVAN was diagnosed in 2.8% of patients during the 1st year post-transplant. Fig. 1 depicts the time-to-BKPyV viremia and Bx-proven BKPyVAN over five years post-transplant. 4/26 (15.4%) of presumptive BKPyVANs and 2/8 (25%) of Bx-proven BKPyVANs were found after two years post-transplant. One patient with Bx-proven BKPyVAN lost his graft 4 months after BKPyVAN diagnosis; in 4 recipients (50%), transplant function stabilized at a lower level (60% of eGFR prior to BKPyVAN). Graft function recovered completely in 3 patients (37.5%) after minimization or conversion of the immunosuppressive regimen. Risk factors associated with BKPyV viremia were younger recipient age (p = 0.002), acute rejection before onset of BKPyV viremia (p < 0.001) and tacrolimus-based immunosuppression (p = 0.001).

Conclusions:

Up to 25% of BKPyVAN develop later than two years after KTx, possibly as a consequence of a reduced BKPyV-specific cellular immune response of pediatric patients. Hence, in pediatric kidney allograft recipients, surveillance for BKPyV viremia should be extended beyond the 2nd year post-transplant.