DETECTION AND SEMIQUANTITATIVE ANALYSIS OF HUMAN-HERPESVIRUS-8 DNA INSPECIMENS FROM PATIENTS WITH KAPOSIS-SARCOMA

Kaposi's sarcoma (KS) is the most common neoplasm in patients with AID S. Epidemiologic evidence and the recent identification of herpesvirus -like DNA sequences in patients with KS have suggested a role for vira l agents in the etiopathogenesis of this disease. It is unclear if the se sequences are present in all types of KS and if the copy number of these sequences has a correlation with disease severity (staging), In order to clarify these issues, we retrospectively analyzed, by PCR and Southern blotting, formalin-fixed, paraffin-embedded biopsy specimens from 12 patients previously diagnosed with KS by histopathologic exam ination of these specimens between the years of 1977 and 1996. We also analyzed tissue samples from these patients taken from dermal sites w ithout KS lesions and control tissues from healthy subjects. Of the 12 patients, 6 had classic KS, 5 had AIDS-associated KS, and 1 had the e ndemic type of KS, We tested the specimens for other herpesviruses, in cluding cytomegalovirus, human herpesvirus 6 (HHV-6), HHV-7, HHV-8, an d Epstein-Barr virus, Of 20 biopsy specimens from patients previously diagnosed with KS, 19 were positive for HHV-8 sequences (95%), while P CR for the DNAs of other herpesvirus agents was negative, Uninvolved t issue from these patients and control tissue from healthy subjects gav e negative results for all viruses. Semiquantitative analysis of South ern blots showed higher levels of HHV-8 DNA in those patients with mul ticentric and visceral involvement than in those patients with localiz ed involvement. In addition, in patients with localized skin disease, the nodular stage had higher levels of HHV-8 DNA than the patch or pla que stages. Our data confirmed that HHV-8 is involved in the etiopatho genesis of all types of KS and that there is a correlation between HHV -8 DNA load and the severity and staging of this disease.