In vivo and in vitro evidence for an association between the route-specific transmission of HHV-8 and the virus genotype

The study was performed to determine if there is an association between the genotype and transmission of HHV‐8 types A and C. These HHV‐8 subtypes are prevalent in the area of North of Sardinia, which is an island off west Italy's mainland that has a high HHV‐8 seroprevalence (35%). Blood and saliva samples from 30 patients with classic Kaposi's sarcoma who were lifetime residents of North Sardinia were analyzed to identify the HHV‐8 genotype and quantitate the viral load. Genotype A, especially A1 subtype, was found more frequently (9/30 patients) and had a significantly higher viral load in saliva compared to blood (P = 0.029), where type C was found more frequently but with a viral load lower than 10³ copies/ml. To determine if there is a correlation between the viral genotype and cellular tropism, type A1 and C3 HHV‐8 viral particles were obtained from cell lines BCBL1 and BC3 infected chronically with HHV‐8 A1 and C3 genotypes respectively and used to infect HEK293 epithelial origin cells and PBMCs in vitro. The data indicate that the A1 HHV‐8 genotype is tropic and replicates at higher levels in the epithelial cell lines. J. Med. Virol. 84:786–791, 2012. © 2012 Wiley Periodicals, Inc.