Soroprevalencia e epidemiologia molecular do herpesvirus humano 8 (HHV-8) em populações brasileiras

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

CHANG et al first identified human Herpesvirus Type 8 (HHV-8) in 1994 from skin biopsies of patients with Acquired Immunodeficiency Syndrome (AIDS) associated Kaposi?s Sarcoma (KS). HHV-8 is an oncovirus from the Herpesviridae family, Gamaherpesvirinae subfamily and Rhadinovirus genus. It is the only one of its genus to infect humans. Its ultra structure reminds other herpesvirus, presenting DNA regions similar to two gama-herpesvirus: Epstein-Barr Virus (EBV) and Saimiri Herpesvirus (SHV), both with oncogenic potential. Studies have revealed the association between HHV-8 and all forms of KS: classic, endemic, related to AIDS and associated to transplants, besides other lymphoid proliferative diseases related or not to AIDS, such as primary effusion lymphoma (PEL), body cavity lymphoma (BCBL) and Castleman´s disease (CD). In this study, using indirect immunofluorescence serologic assays, it was possible to determine that HHV-8 is endemic in two Amerindian tribes (Tiriyo and Waiampi), from the Amazon region. Anti-HHV-8 antibodies were detected in 56.8% of the Amerindians (558/982), in all ages (0-81 years old) and both sexes. In these populations, high prevalence in children younger than 2 years old (44.4%) and children from 2 to 9 years old (35.0%) suggests non-sexual routs of transmission of HHV-8, through vertical transmission or contact to contaminated secretions. HHV-8 seroprevalence in blood donors from Campinas was low (2.8%). All positive cases were male (9/319) with 31 to 50 years of age. Curiously, all KS patients assessed in our study were male and anti-HHV-8 antibodies were detected in all cases. Genotyping of HHV-8 through sequencing of hypervariable regions of the viral genome, such as ORF-K1, made possible formulate a classification of the main viral subtype (A, B, C, D and E) and its variants. In order to perform HHV-8 genotyping, we standardized molecular techniques for amplification and sequencing of two fragments (VR1 and VR2) from the hypervariable ORF-K1 region of HHV-8, building up phylogenetic trees and determining viral subtypes. Patients with SK from the city of Campinas had subtypes A, B and C detected, with greater frequency of subtype C. Subtypes A and E were detected in Amazonic Amerindians. This study was the first to perform genotyping in samples of patients with Human Immunodeficiency Virus (HIV) positive serology from the city of Salvador, detecting subtype B and an undetermined subtype. Thus, it was possible to determine that HHV-8 subtypes A, B, C and E are present in Brazilian populations. All nucleotide sequences of HHV-8 fragments VR1 and VR2 found during this study will be deposit at the NCBI/Nucleotide Sequence Database (GenBank), informing the scientific community with important data of HHV-8 strains in Brazil. Analysis of samples from blood donors and Kaposi?s Sarcoma in Campinas, HIV positive patients in Salvador and Amerindians from the Amazon region made up a databank of seroprevalence and molecular epidemiology of HHV-8 in Brazilian populations. The knowledge of serological and molecular techniques developed in this study may be used by Molecular Biology Laboratories at Unicamp and LASP/Fiocruz, allowing the implantation of HHV-8 diagnostic and genotyping techniques in these centers

ASSUNTO(S)

sarcoma de doadores de sangue kaposi transmissão vertical de doença prevalencia herpesvirus 8 humano

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