SEATTLE--DNA from the recently discovered Kaposi's sarcoma-associated herpesvirus (KSHV) has been isolated in KS lesions as well as some AIDS-related lymphomas, and the new research suggests that foscarnet (Foscavir) may effectively inhibit the virus. Enrique. A. Mesri, PhD, of the Department of Medicine, Cornell University Medical College, reported the findings at the American Society of Hematology (ASH) meeting.
Dr. Mesri and his colleagues at Cornell and Memorial Sloan-Kettering found a DNA fragment from KSHV in a high percentage of both AIDS-related and non-AIDS-related Kaposi's sarcoma lesions. The DNA fragment was also found in cells from AIDS-related body cavity-based B-cell lymphomas (AIDS-BCBL).
The KSHV+ DNA found in BC-1 cells (a cell line established from an AIDS-BCBL patient and the first cell line known to stably carry KSHV-DNA) was protected from DNAse degradation, possibly, the researchers concluded, by being inside a viral capsid.
They also found that KSHV shared DNA homology with Epstein-Barr virus and herpesvirus-Saimiri, both lympho-trophic herpesviruses, Dr. Mesri said.
Further studies found that the KSHV+ viral particles were infective and could transmit KSHV-DNA to human CD19+ B lymphocytes in culture. This in vitro infection could be blocked by the viral DNA-polymerase inhibitor foscarnet, as well as by ultraviolet irradiation, indicating that transmission and persistence of KSHV-DNA is dependent on a 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-based B-cell lymphomas.
