Study Suggests Foscarnet Might Be Useful in Kaposi's Sarcoma

SEATTLE--DNA from the recently discovered Kaposi's sarcoma-associatedherpesvirus (KSHV) has been isolated in KS lesions as well assome AIDS-related lymphomas, and the new research suggests thatfoscarnet (Foscavir) may effectively inhibit the virus. Enrique.A. Mesri, PhD, of the Department of Medicine, Cornell UniversityMedical College, reported the findings at the American Societyof Hematology (ASH) meeting.

Dr. Mesri and his colleagues at Cornell and Memorial Sloan-Ketteringfound a DNA fragment from KSHV in a high percentage of both AIDS-relatedand non-AIDS-related Kaposi's sarcoma lesions. The DNA fragmentwas also found in cells from AIDS-related body cavity-based B-celllymphomas (AIDS-BCBL).

The KSHV+ DNA found in BC-1 cells (a cell line established froman AIDS-BCBL patient and the first cell line known to stably carryKSHV-DNA) was protected from DNAse degradation, possibly, theresearchers concluded, by being inside a viral capsid.

They also found that KSHV shared DNA homology with Epstein-Barrvirus and herpesvirus-Saimiri, both lympho-trophic herpesviruses,Dr. Mesri said.

Further studies found that the KSHV+ viral particles were infectiveand could transmit KSHV-DNA to human CD19+ B lymphocytes in culture.This in vitro infection could be blocked by the viral DNA-polymeraseinhibitor foscarnet, as well as by ultraviolet irradiation, indicatingthat transmission and persistence of KSHV-DNA is dependent ona biologically active replicating virus.

Dr. Mesri and his colleagues plan to pursue the potential of foscarnet,currently approved by the FDA for the treatment of CMV retinitis,as a treatment for Kaposi's sarcoma and AIDS-related body cavity-basedB-cell lymphomas.