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BKPyV-DNAemia is common after kidney transplant but rarely leads to graft loss or death, likely due to improved screening and management practices.

Although BK polyomavirus (BKPyV)–DNAemia was prevalent in kidney transplant recipients in a single-center study, associated graft loss rates were low, with no demonstrable effect on long-term graft loss or patient mortality, according to findings published in the journal Nephrology.

The findings showed “improved graft survival compared to previous eras, which may reflect surveillance practice that has subsequently been intensified in line with more recent guidelines,” Alyssa Pradhan, MBBS, and colleagues wrote.

Over the past decade, expert guidance has increasingly recommended BKPyV-DNAemia screening for kidney transplant recipients. The study investigated the prevalence of BKPyV-DNAemia in 522 adult patients who received a kidney transplant between 2010 and 2018. Between 65% and 85% of patients in the cohort were screened at 1, 3, 6, and 12 months after kidney transplant or when clinically indicated. Current practice adheres to more recent surveillance guidance, the researchers noted, with screening monthly until month 9 and then every 3 months until 2 years after transplant.

Among the 522 patients in the analysis, 100 patients (19%) developed BKPyV-DNAemia, according to the study results, and 43 patients (8.2%) developed biopsy-confirmed BKPyV-nephropathy, which resulted in the loss of two grafts.

“Overall, there were no clear risk factors that predisposed to BKPyV-nephropathy or graft loss,” Dr. Pradhan and colleagues wrote.

Factors Associated With BKPyV-DNAemia

The study did identify several factors associated with the development of BKPyV-DNAemia. Odds ratios (ORs) were 2.53 in patients with human leukocyte antigen (HLA) mismatch of 5/6 and 6/6, 2.37 in patients with HLA mismatch of 3/6 or 4/6, 2.06 in patients with pretransplant diabetes, and 1.76 in patients from racial and ethnic minority groups, the researchers reported.

“Additionally, a greater than 25 mg per day prednisolone dose following acute transplant and acute rejection in the first month post-transplant was associated with an increased risk of BKPyV-DNAemia,” they continued, with ORs of 3.06 and 2.36, respectively.

In an analysis of 502 patients with long-term graft and patient survival data, neither BKPyV-DNAemia nor BKPyV-nephropathy was associated with reduced graft or patient survival over 10 years of follow-up.

“This work shows that, at the time, our approach to managing BKPyV-DNAemia was successful in the majority of cases,” Dr. Pradhan and colleagues wrote. “Further prospective and randomized trials incorporating the updated surveillance guidelines are needed to further characterise optimal management.”