title: Lack of tax diversity for tropical spastic paraparesis/human T-cell lymphotropic virus type 1 (HTLV-I) associated myelopathy development in HTLV-I-infected subjects in São Paulo, Brazil.
abstract: The product of human T-cell lymphotropic virus type 1 (HTLV-1) tax gene has a transactivating effect of the viral and cellular gene expression. Genetic variations in this gene have been correlated with differences in clinical outcomes. Based upon its diversity, two closely related substrains, namely tax A and tax B, have been described. The tax A substrain has been found at a higher frequency among human T-cell leukemia virus type 1 (TSP/HAM) patients than among healthy HTLV-I-infected asymptomatic subjects in Japan. In this study, we determined the distribution of tax substrains in HTLV-I-infected subjects in the city of São Paulo, Brazil. Using the ACCII restriction enzyme site, we detected only tax A substrain from 48 TSP/HAM patients and 28 healthy HTLV-I carriers. The sequenced tax genes from nine TSP/HAM patients and five asymptomatic HTLV-I carriers showed a similar pattern of mutation, which characterizes tax A. Our results indicate that HTLV-I tax subtypes have no significant influences on TSP/HAM disease progression. Furthermore, monophyletic introduction of HTLV-I to Brazil probably occurred during the African slave trade many years ago.
authors.affiliation: Ambulatório de HTLV, Instituto de Infectologia, Emílio Ribas, São Paulo, SP, 05403-000, Brasil. jorge_casseb@yahoo.com.br
authors.forename: J
authors.initials: J
authors.lastname: Casseb
authors.forename: Lmi
authors.initials: L
authors.lastname: Fukumori
authors.forename: Mpp
authors.initials: M
authors.lastname: Vergara
authors.forename: S
authors.initials: S
authors.lastname: Sanabani
authors.forename: Pe
authors.initials: P
authors.lastname: Marchiori
authors.forename: Ajs
authors.initials: A
authors.lastname: Duarte
authors.forename: Acp de
authors.initials: Ad
authors.lastname: Oliveira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D016356:Gene Products, tax / Q000235:genetics*; D014644:Genetic Variation; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015493:Paraparesis, Tropical Spastic / Q000821:virology*; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D016356:Gene Products, tax