Kaposi's sarcoma (KS) is a previously rare, tumour-like lesion of controversial biological nature. KS has since the early 1980s become frequent in patients with AIDS, particularly in homosexuals. KS is also endemic in Central Africa predominantly in otherwise healthy men but also in women and children. Recently, evidence for the presence of novel, herpes virus DNA sequences in more than 90% of AIDS Kaposi lesions (AKS) was presented. This DNA was identified using representational difference analysis (RDA) generating short, unique sequences with variable homology to several herpes virus, but no intact virus was recovered. If these DNA-sequences are also present in other, non-HIV-associated forms of Kaposi's sarcoma this would strongly suggest a specific, aetiopathological involvement of this putative new herpes virus in the pathogenesis of Kaposi's sarcoma, rather than a contamination of yet another opportunistic virus in immunosuppressed AIDS patients.
PIP: Samples were examined by polymerase chain reaction (PCR) for the presence of the putative Kaposi's sarcoma herpes virus (KSHV). KS DNA from HIV-negative, African, endemic (EKS) samples, and epidemic HIV-positive KS (AKS), and sporadic KS (SKS) samples were tested from Tanzania and Sweden. All of the HIV KS (18 African EKS and 4 Swedish SKS) as well as the HIV-positive AIDS-related KS (16 African and 7 Swedish AKS) biopsies were shown to contain the previously described DNA sequences. KS lesions from children, females, and males in various tissues were analyzed including skin, lymph nodes, gut and oral mucosa. All forms of KS showed a single PCR product of the expected size (233 base pairs). To exclude amplification of other types of herpes virus, virus preparations of Epstein-Barr virus (EBV), herpes simplex virus, cytomegalovirus, vesicular stomatitis, and human herpes virus type 6 (HHV6) were assayed, again by PCR, using the KSHV primers. No PCR products were obtained with any of these virus strains. However, most HIV-positive and HIV-negative KS DNA samples also contained either EBV and/or HHV6 sequences. All biopsies from non-KS tissues (cells) of HIV-positive and HIV-negative individuals were consistently negative for KSHV by PCR. The observation that the same herpes virus-like DNA sequence is present in endemic and sporadic, as well as AIDS-related, Kaposi's sarcoma cases suggests a possible pathogenic association between this putative novel, herpes-like virus and KS. The herpes virus-like DNA sequences described by Y. Chang in 1994 may indeed represent a novel herpes (KSHV), etiopathologically associated with various clinical forms of Kaposi's sarcoma. Its pathogenic importance is indicated by its presence in different KS tissues with various clinical types of KS and its absence from non-KS-involved tissues. Furthermore, the presence of KSHV in KS of children suggests a nonsexual mode of transmission.