Kaposi's-sarcoma-associated herpesvirus is detected in peripheral blood mononuclear cells of HIV-infected homosexuals more often than in heterosexuals.

Purpose: The Kaposi's-sarcoma-associated herpesvirus is thought likely to play an important part in the pathogenesis of Kaposi's sarcoma, which is the most common tumor in AIDS patients. To determine whether peripheral blood is also infected by the virus, we prospectively tested mononuclear cells from HIV-infected individuals, both with and without Kaposi's sarcoma.

Patients And Methods: Thirty-three patients with AIDS were studied. Twenty-three were homosexuals, and 10 of these patients had Kaposi's sarcoma. All 10 nonhomosexual patients were free of Kaposi's sarcoma. PCR amplification of peripheral blood mononuclear cells was performed for a 233-base-pair segment of Kaposi's-sarcoma-associated herpesvirus on all patients. Fisher's exact test was used to compare the patient groups.

Results: Kaposi's-sarcoma-associated herpesvirus sequences were detected in the peripheral blood mononuclear cells of homosexual men both with (7/10) and without (5/13) Kaposi's sarcoma. However, none of the nonhomosexual patients (0/10) had detectable virus. Therefore, those with Kaposi's sarcoma are at greater risk for Kaposi's-sarcoma-associated herpesvirus infection than patients without Kaposi's sarcoma, and among HIV-positive patients without Kaposi's sarcoma, homosexuals are more likely to have detectable Kaposi's-sarcoma-associated herpesvirus than are nonhomosexuals. In the homosexual patients, the presence of virus was unrelated to total CD4+ cell counts. A comparative dilutional analysis showed that the nonhomosexual patients had a low viral load in their peripheral blood mononuclear cells relative to most homosexuals with Kaposi's sarcoma. Sequential studies on two patients revealed clearing of the virus while on therapy; one patient was treated for HIV with the protease inhibitor indinavir, and the other patient was treated for Kaposi's sarcoma with liposomal doxorubicin.

Conclusions: These results indicate that Kaposi's-sarcoma-associated herpesvirus is harbored in peripheral blood mononuclear cells of HIV-infected patients, and that the rates of infection are significantly higher in homosexual men compared with their nonhomosexual counterparts. The significance of viral clearing in response to therapy is unknown but warrants further study, as prophylactic treatment for this virus might alter the occurrence of Kaposi's sarcoma in this susceptible patient population.