HHV-8 variants in Kaposi's sarcoma patients:: phylogenetic and phenetic analysis

HHV-8 isolated from 73 HIV-positive or HIV-negative KS patients. recruited in Europe. Africa and Americas, have been characterized bq nucleotide sequence and phylogenetic analysis of ORF36 and 72, which encode for the minor capsid protein and Cyclin-D homolog, respectively. Our results show that the virus is highly consented, with ORF72 overall variability; <1%. Within the ORF26 (918-bp)21 point mutations (2.28%) have been detected. 15 fall in the 349-516 region (8.92%), with a ds/dn ratio >3.0 and low antigenic index suggesting that binding affinity plays a role more relevant than immunological selection. Specific nucleotide point mutations present in the ORF26 allow identification of five major viral variants. In each analysed geographical region more than a single variant is present. although in different combinations. Phylogenetic analysis, performed by the Clustal method and Bootstrap analysis. identifies three major branches, whose distribution is prevalently related to ethnic/geographical factors more than KS type and degree of malignancy.