HPyV9 infection frequent among kidney transplant recipients

By van der Meijden E-www.healio.com
Published on June 5, 2014

Human polyomavirus 9, or HPyV9, infection is prevalent in immunosuppressed kidney transplant recipients, although the pathogenicity of this virus is not fully understood, according to recent findings.

“Because HPyV9 was originally isolated from a kidney transplant recipient, we aimed to systematically study the presence of HPyV9 infection in kidney transplant patients and investigate a possible association with the known nephropathogenic [BK polyomavirus],” researchers wrote in Emerging Infectious Diseases.

In the study, the researchers evaluated 101 patients undergoing kidney (n=83) or kidney-pancreas transplantation (n=18) between 2002 and 2004 at Leiden University Medical Center in Leiden, the Netherlands. They collected serum samples during the 18 months after transplantation, assessing the presence of HPyV9 DNA (n=65) and immunoglobulin G antibodies (n=45). The samples were compared with a control group of 87 unidentified, unpaid, age- and gender-matched blood donors. The researchers also tested samples for cytomegalovirus.

“Whether HPyV9 is pathogenic in immunocompromised patients, alone or in concert with the well- known pathogen (BK polyomavirus), deserves further study.”

The researchers found that 21 of the 101 patients had positive results for HPyV9 DNA at some point during the study. The rates of positivity peaked at 3 months post-transplantation. However, the most substantial viral loads were discovered shortly after transplantation. During the 18-month follow-up, the rate of HPyV9-positive blood tests increased from 33% to 46% among the transplant patients while the rate of seroprevalence among healthy donors without HpyV9 DNA remained at about 30%. Additional analysis revealed a correlation between the identification of HPyV9 and detection of BK polyomavirus but not cytomegalovirus.

According to the researchers, it is unclear whether the frequent incidence of HPyV9 among kidney transplant patients is endogenous or donor-originated.

“The observed prevalence of HPyV9 DNA in serum samples considerably exceeded detection rates of HPyV9 found by others in skin samples of immunocompetent and immunocompromised persons, which suggests that HPyV9 causes systemic rather than skin infection,” the researchers wrote.

Disclosure: The researchers report no relevant financial disclosures. June 4, 2014

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