Human herpesvirus 8 (HHV-8) in familial Kaposi's sarcoma

: Human herpesvirus 8 (HHV-8) has been detected in various epidemiological forms of Kaposi's sarcoma (KS). Since familial KS cases are exceedingly rare and the occurrence of familial KS in siblings has thought to depend rather on genetic factors than on a viral factor, familial KS has not been investigated for the presence of HHV-8. To investigate whether HHV-8 is present also in this rare form of KS, we examined tumor biopsies of 2 siblings with familial KS for the presence of HHV-8 specific DNA sequences by a nested PCR protocol. HHV-8 DNA sequences could be detected in KS specimens of both patients. Sequence analysis revealed an identical DNA sequence of HHV-8 in KS tissue of both siblings, but the sequence in our cases differs in one base pair at position 67 from the previously published HHV-8 KS330Bam fragment. The findings indicate that besides the yet poorly defined genetical factors involved in the pathogenesis of KS, HHV-8 may act as a cofactor also in familial KS. In addition, our data demonstrate that HHV-8 is found in all epidemiological forms of KS, including the rarely occuring familial KS. Familial KS may act as a further model to study the interaction of an oncogenic virus with genetic host factors in the context of a neoplastic disorder.