Effect of polyoma viremia on 3‐year allograft kidney function

Abstract

Background Polyoma viremia is associated with damage to renal tubular and urothelial cells. This may imply that a certain level of viremia, even cleared thereafter, could be associated with long‐term renal dysfunction. Methods We, retrospectively, analyzed 390 first renal transplants adult recipients (≥18 years) who were monitored for BK viremia in the first 12 months and evaluated estimated GFR (MDRD‐4 equation) at 1 month and at the last follow‐up (959 ± 392 days). Results One hundred and ninety‐nine patients (51%) developed at least one positive viremia: 105 (53%) low viremia (<104 copies/mL), 36 (18%) high viremia (4 × 104 > viremia ≥ 104 copies/mL) and 58 (15%) viremia (≥4 × 104 copies/mL) consistent with polyoma virus associated nephropathy (PyVAN). Out of these 58 patients, 24 (6%) developed bx‐proven (SV40+) PyVAN and 34(8.7%) presumptive PyVAN (SV40−). Baseline characteristics, immunosuppression, KDRI, rejection episodes, etc., did not differ among groups but there were more deceased donors and ATG induction therapy in the high viremia group. At last follow‐up, all patients in the low, high viremia and presumptive PyVAN (except 2) had cleared BK viremia. Bx‐proven PyVAN led to 14 graft losses, 10 due to PyVAN. In the presumptive PyVAN there was only one graft loss registered as due to PyVAN. eGFR, at 1 month after KTx, did not differ among groups (51 ± 22 vs 48 ± 24 vs 45 ± 27 vs 43 ± 18 vs 46 ± 22 mL/min/1.73 m2), for no, low and high viremia as well for presumptive PyVAN and bx‐proven PyVAN groups, respectively. At the last follow‐up, eGFR did not differ between the no, low, and high viremia compared to baseline and to each other but was statistically lower in the presumptive and bx‐proven PyVAN (38 ± 15 and 17 ± 7 mL/min/1.73 m2) either compared to baseline or to the other groups. Conclusions This study shows that low and high levels of BK viremia do not lead to GFR changes although very high viremia levels, compatible with presumptive or bx‐proven PyVAN, even if cleared thereafter, lead to allograft damage and decreased GFR.

A multicenter prospective study to define the natural history of BK viral infections in kidney transplantation

“…This is a relatively high incidence compared to the three large cohort studies mentioned above, where BKVN rates ranged from 0%-10%. [21][22][23] Whereas our association of biopsyproven BKVN with a decline in eGFR was somewhat expected, we also found that persistent BK viremia (reflected by participants that remained in the intensive phase) was associated with a decline in eGFR, consistent with some previous studies 1,30 but not others. 16,18,23 This is important when considering the design of future clinical trials of the antiviral therapy, since powering differences in BK viremia would require a smaller trial size than one with BKVN as the primary outcome.…”

Risk factors and outcomes of BK viremia among deceased donor kidney transplant recipients based on donor characteristics

“…In a previous study, Hertz-Tang et al 24 found no significant increase in the risk of adverse outcomes including rejection, infection, and graft failure in patients with BK viremia in the absence of BKN compared to patients without BK viremia. In their study on 3-year graft function following BK viremia, David-Neto et al 25 found that only very high levels of viremia, those with viral loads compatible with presumptive or biopsy-proven BKN, lead to poor graft outcomes. Low and high levels did not.…”

Protocolized polyoma BK viral load monitoring and high-dose immunoglobulin treatment in children after kidney transplant

“…Preemptive monitoring of BKPyV viral load by real-time polymerase chain reaction (RT-PCR) is essential for early diagnosis of BKPyV replication. Persistently elevated BKPyV viral loads exceeding 10 7 copies/mL in urine or 10 4 copies/mL in blood over a three-week period are highly associated with BKPyVAN risk [ 11 ]. Of note, while blood BKPyV monitoring is considered as routine practice by most transplantation centers, the significance of urine BKPyV monitoring is controversial.…”