Molecular Typing of Human Herpesvirus 8 Isolates from Patients with Kaposi's Sarcoma in Hungary

Background: Kaposi's sarcoma (KS) shows a distinct geographical and ethnic distribution. Genes at both ends of the human herpesvirus 8 (HHV-8) genome have been shown to vary considerably. Seven major molecular subtypes of HHV-8 were defined based on the amino acid sequence of the open reading frame K1 (orf-K1). The aim of the present study was to characterize HHV8 isolates from hospitalized patients in Hungary. Materials and Methods: A total of 36 archival paraffin-embedded Kaposi's sarcoma tissue samples were collected. Polymerase chain reaction (PCR) was carried out on the extracted DNA, using specific primers for HHV-8. After identifying the presence of HHV-8 by amplification of its orf26 region, the orf-K1 region was amplified, sequenced and used for phylogenetic analysis. Results: From the 36 orf26-positive cases, orf-K1 was amplified and was analyzed successfully in 12 cases. Phylogenetic studies, based on the complete K1 gene/protein sequences, indicate that all strains belong to the A subtype. Specifically, six of them were related to the A1 subgroup, six to the A2 subgroup and three previously reported to the A3 subgroup. Nucleotide sequence data are reported and are available in the Genbank database under accession numbers KF829938-KF829947.