Researchers identified herpesvirus-like DNA sequences in AIDS-associated Kaposi's sarcoma (KS) using representational difference analysis (RDA). This method allowed them to isolate unique DNA sequences present in over 90% of KS tissues from AIDS patients but absent in non-AIDS patients. These sequences were distinct from those of known herpesviruses, including capsid and tegument protein genes of the Gammaherpesvirinae, herpesvirus saimiri, and Epstein-Barr virus. The sequences were found to be homologous to herpesviral polypeptides and appeared to define a new human herpesvirus. The study confirmed the presence of these sequences in KS tissues through Southern blot hybridization and PCR amplification. The sequences, designated KS330Bam and KS631Bam, showed high homology to herpesvirus saimiri ORF26 and Epstein-Barr virus BDLF1. These sequences were specifically associated with KS in AIDS patients, with high detection rates in KS tissues compared to non-KS tissues. The sequences were not found in non-KS tissues, including those from AIDS patients, suggesting an infectious origin. The study also demonstrated that these sequences were not heritable polymorphic markers, as unaffected tissues from AIDS patients were generally negative for these sequences. The results indicated that the sequences were likely associated with the KS phenotype and not a result of HIV infection. The findings suggest the presence of a new human herpesvirus in KS lesions, although a causal link to AIDS-KS could not be definitively established. The study was supported by NIH grants and was independently confirmed through PCR analysis.Researchers identified herpesvirus-like DNA sequences in AIDS-associated Kaposi's sarcoma (KS) using representational difference analysis (RDA). This method allowed them to isolate unique DNA sequences present in over 90% of KS tissues from AIDS patients but absent in non-AIDS patients. These sequences were distinct from those of known herpesviruses, including capsid and tegument protein genes of the Gammaherpesvirinae, herpesvirus saimiri, and Epstein-Barr virus. The sequences were found to be homologous to herpesviral polypeptides and appeared to define a new human herpesvirus. The study confirmed the presence of these sequences in KS tissues through Southern blot hybridization and PCR amplification. The sequences, designated KS330Bam and KS631Bam, showed high homology to herpesvirus saimiri ORF26 and Epstein-Barr virus BDLF1. These sequences were specifically associated with KS in AIDS patients, with high detection rates in KS tissues compared to non-KS tissues. The sequences were not found in non-KS tissues, including those from AIDS patients, suggesting an infectious origin. The study also demonstrated that these sequences were not heritable polymorphic markers, as unaffected tissues from AIDS patients were generally negative for these sequences. The results indicated that the sequences were likely associated with the KS phenotype and not a result of HIV infection. The findings suggest the presence of a new human herpesvirus in KS lesions, although a causal link to AIDS-KS could not be definitively established. The study was supported by NIH grants and was independently confirmed through PCR analysis.