NEW ORLEANS — A virus associated with Kaposi’s sarcoma has been detected in the saliva of six of seven HIV-infected gay men with a current or previous history of Kaposi’s sarcoma, report University of Washington researchers.
Kaposi’s sarcoma is a form of cancer that is often especially virulent in people with compromised immune systems, such as AIDS patients. A new herpes virus, now termed Kaposi’s sarcoma-associated herpes virus (KSHV or HHV8), was detected in 1994 in Kaposi’s sarcoma lesions. However, the mode of transmission of KSHV has been unknown.
“While salivary contact has not been proven to be a mechanism of KSHV transmission, it is possible that such contact may spread the infection,” said first author Dr. David Koelle, assistant professor of medicine at the University of Washington in Seattle. “Persons with and without clinical signs of Kaposi’s sarcoma may shed KSHV and possibly be sources of infection.”
Koelle presents his team’s findings on Sept. 18 in New Orleans at the 36th Interscience Conference on Antimocrobial Agents and Chemotherapy, sponsored by the American Society for Microbiology.
Koelle notes that Kaposi’s sarcoma occurs much more frequently in gay and bisexual men with HIV infection than in persons who acquire HIV infection by means other than homosexual contact, such as injection drug use or transfusions. Up to 20 percent of HIV-infected gay or bisexual men develop Kaposi’s sarcoma prior to death, and epidemiologic data are consistent with Kaposi’s sarcoma as a sexually transmittable agent. Risk factors include the number of sexual partners, a history of other sexually transmitted diseases, and anal sexual contact.
(Kaposi’s sarcoma also occurs in non-HIV-infected people, especially elderly men in southern Europe, and in Africa, both in adults and as an aggressive form in infants.)
Since KSHV is genetically related to Epstein-Barr virus, which is spread through saliva and causes infectious mononucleosis, the UW researchers theorized that KSHV might also be present in saliva and perhaps spread by this route. They used a method called polymerase chain reaction to detect the presence of the DNA of KSHV in the saliva of the seven men, and found the amount of KSHV was relatively high, up to one million DNA copies per milliliter of saliva.
An additional test using DNA-destroying enzymes determined that whole, infectious virus was also present. In addition, an attempt was made to grow the virus in culture. While high-level infection was not achieved, the researchers obtained data consistent with transmission of KSHV from saliva to cultured cells.
“While the relationship between KSHV infection and Kaposi’s sarcoma has not been formally proven, it is highly likely that infection with the virus is required for development of the disease,” said Koelle, who noted other examples of infectious agents causing cancer: hepatitis B (liver cancer), human papilloma virus (cervical cancer) and Epstein-Barr virus (lymphoma).
“Our findings raise concern over the possibility that saliva may play a role in transmission of this newly discovered herpes virus,” said Koelle. “Knowledge of KSHV and the risk of disease is still very rudimentary. It may be prudent to avoid contact with potentially infectious body substances, including saliva, until additional information is available.”
Co-investigators, all at the University of Washington, are Dr. Meei-Li Huang, Dr. Jeffrey Vieira, David Berger, Dr. Michael Piepkorn and Dr. Lawrence Corey. The research was funded by the National Institutes of Health.
Laurie McHale, (206) 543-3620 or email@example.com
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