Uncommon testing capability supports CDC investigation into KSHV-infected organ transplants

A team of scientists at the Frederick National Laboratory for Cancer Research is a key partner to the U.S. Centers for Disease Control and Prevention in its efforts to investigate reports of suspected solid organ-donor derived Kaposi sarcoma-associated herpesvirus (KSHV) which has increased more than five-fold in the last five years.

Denise Whitby, head of the Viral Oncology Section in the AIDS and Cancer Virus Program and a recognized global leader in the KSHV community, is with her team helping the CDC investigate the growing number of U.S. organ transplant recipients who develop Kaposi sarcoma (KS), caused by infection with KSHV.

The CDC reported in a March 5 Morbidity and Mortality Weekly Report during January 2021-September 2025, after transplantation of 185 organs into 153 recipients, 46 deceased donors were identified whose transplanted organs were suspected of having potentially transmitted KSHV. As of June 2026, 79% of donors and 50% of these transplant recipients tested as KSHV positive.

The increase in KSHV-associated disease in transplant recipients indicates the need for strategies to increase testing capacity to enable testing of donors and recipients that could help mitigate potential KSHV complications among recipients. 

Testing of donors and recipients for KSHV is not routinely performed, given the limited availability of commercially available tests and the current absence of consensus screening guidelines.

CDC calls on Whitby lab’s expertise and advice  

Whitby leads one of the few U.S. laboratories that performs KSHV testing. She studies KSHV-related diseases, which in the U.S. occur most frequently in men who have sex with men, including people with HIV, and she has developed serological and PCR assays for KSHV. 

Her team and academic colleagues recently reported a study in Clinical Infectious Diseases that KSHV infection among kidney donors and recipients with HIV was high, but incidence of associated disease was rare.  

Most donors and recipients in the CDC report were HIV negative, and nonmedical drug use was common among donors. Whitby said she and her team investigated samples from a subset of the CDC group and found 19 of 24 deceased organ donors whose recipients developed Kaposi sarcoma disease tested positive for the virus. 

KSHV-related complications can result from reactivation of latent infection, new post-transplant infection not directly related to the transplant or transmission of KSHV from the transplanted organ. 

Reports of donor-derived KSHV infection are relatively uncommon, the CDC report said, and in general, the benefits of transplantation outweigh the risk for infection.  

CLIA-certified assay required for continued KSHV testing 

The analysis of samples from deceased organ donors with the CDC was conducted using a research-use only assay developed in the Viral Oncology Section. For testing of living individuals, the test used must be certified according to federal regulations that require laboratory testing performed on living humans meet the requirements of the Clinical Laboratory Improvement Amendments of 1988 (CLIA). 

A key next step in the Whitby lab’s collaboration with CDC is to develop a CLIA-certified KSHV serological assay to enable KSHV testing of living organ donors and recipients. Such assays are not currently available. 

Compared to viruses such as HIV, HPV and hepatitis B, serology testing for KSHV is complex. Testing for other viruses may only require detection of antibodies targeting a single viral antigen, Whitby said. Because antibody responses to KSHV are more heterogenous than for most other viruses, testing for KSHV requires multiple antigens. 

The CLIA-certified test for CDC investigations will use five antigens to achieve maximum sensitivity, she said.

Additional ACVP authors on the Clinical Infectious Diseases study include Nazzarena Labo, Wendell Miley and Vickie Marshall.