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Kidney Week

Abstract: FR-PO1102

Everolimus Suppresses the BK Virus Replication in Human Embryo Cells In Vitro

Session Information

  • Transplantation: Basic
    November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

  • 1901 Transplantation: Basic


  • Sato, Noriaki, Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Mori, Keita P., Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Sakai, Kaoru, Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Tanabe, Kazunari, Tokyo Women's Medical University, Shinjuku-ku, ToKyo, Japan
  • Yanagita, Motoko, Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Shiraki, Kimiyasu, Senri Kinran University, Suita, Osaka, Japan

BK virus causes BKV-associated nephropathy in about 8% of kidney transplant patients and allograft loss occurs in 10-50% of the affected individuals. There is currently no effective treatment for BKV and it is mainly treated by reducing immunosuppression or changing the treatment regimen. Therefore, the search for effective treatments and mechanisms for BK virus infection is important. To date, various immunosuppressants were reported to suppress the replication of BKV in vitro. However, there are few reports that showed the effects of everolimus. We report the in vitro study of the effects of everolimus on BKV proliferation.


Confluent human embryo lung cells were infected with BKV isolated from a renal transplant recipient. We first determined the replication time and viral infectivity in this system. BKV DNA replication was evaluated by the increase in the DNA copy numbers in infected cells and the tissue culture infectious dose (TCID50) and viral copy number were determined in three viral stocks. Effects of immunosuppressants on BKV replication were examined in this system. Cells were infected and treated with everolimus, cyclosporine, and tacrolimus at various concentrations attained in the recipients for 72 hours and the amounts of the replicated viral DNA were determined by a real-time quantitative PCR with primers targeting the large T-antigen.


BKV growth curve showed that BKV DNA increased at 48 hours and further at 88 hours after infection, indicating one replication cycle was 48 hours. Viral infectivity was attained at 108 to 109 TCID50/mL and particle per infectivity ratio was 2.12 TCID50/1,000 DNA copies (n=3) in this system. BKV replication was not affected by treatment with tacrolimus and cyclosporine at concentrations from 1 to 30 ng/mL and from 0.01 to 1 μg/mL, respectively. Everolimus at concentrations from 0.1 to 300 ng/ml significantly suppressed BKV replication to 20 to 40% of untreated cells.


Everolimus has been reported to alleviate BKV infection in the TRANSFORM study. Everolimus suppressed BKV replication at the concentrations attained in the serum of renal transplant recipients and this results support the alleviation of BKV infection with everolimus.