Identification of Human T-lymphotropic Virus Type I (HTLV-I) Subtypes Using Restrited Fragment Length Polymorphism in a Cohort of Asymptomatic Carriers and Patients with HTLV-I-associated Myelopathy/tropical Spastic Paraparesis from São Paulo, Brazil

Abstract

Although human T-lymphotropic virus type I (HTLV-I) exhibits high genetic stability, as compared to other RNA viruses and particularly to human immunodeficiency virus (HIV), genotypic subtypes of this human retrovirus have been characterized in isolates from diverse geographical areas. These are currently believed not to be associated with different pathogenetic outcomes of infection. The present study aimed at characterizing genotypic subtypes of viral isolates from 70 HTLV-I-infected individuals from São Paulo, Brazil, including 42 asymptomatic carriers and 28 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), using restricted fragment length polymorphism (RFLP) analysis of long terminal repeat (LTR) HTLV-I proviral DNA sequences. Peripheral blood mononuclear cell lysates were amplified by nested polymerase chain reaction (PCR) and amplicons submitted to enzymatic digestion using a panel of endonucleases. Among HTLV-I asymptomatic carriers, viral cosmopolitan subtypes A, B, C and E were identified in 73.8%, 7.1%, 7.1% and 12% of tested samples, respectively, whereas among HAM/TSP patients, cosmopolitan A (89.3%), cosmopolitan C (7.1%) and cosmopolitan E (3.6%) subtypes were detected. HTLV-I subtypes were not statistically significant associated with patients' clinical status. We also conclude that RFLP analysis is a suitable tool for descriptive studies on the molecular epidemiology of HTLV-I infections in our environment

Molecular characterization of human T-cell lymphotropic virus coinfecting human immunodeficiency virus 1 infected patients in the Amazon region of Brazil

“…This is in agreement with other studies that indicate this subtype as the most prevalent in urban populations such as São Paulo and Salvador (Segurado et al 2002, Alcântara et al 2003a). In addition, this subtype has been related in other rural communities in the state of Pará (Pontes et al 2003, Vallinoto et al 2004.…”

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

“…Shadowed nucleotides indicate difference from ATK strain. The positional nomenclature of the tax region corresponds to sequence alignment with ATK strain Tax gene 7401 7914 7920 7982 8231 Isolates TSP165 T C T T A A TSP168 T C T T A A TSP23 T C T T A A TSP33 T C T T A A TSP124 T C T T A A TSP126 C T T T A A TSP262D T C T T A A TSP261 T C T T A A TSP318B C T T T A A AS174E T C T T A A AS230B T C T T A A AS257 T C T T A A AS368 T C T T A A AS232D T C T T A A using RFLP on samples from the LTR region, that the majority of patients from São Paulo belonged to the Cosmopolitan A subtype, although other LTR subtypes are also present in this population (Yamashita et al 1999, Segurado et al 2002. The mere detection of tax sub-strain A in our cohort and the high prevalence of viral infection among the African descendents in the North and Northeast of the country (Bendelt et al 2001, Alcantara et al 2003, Laurentino ...…”

“…The Cosmopolitan group is further subdivided into four subgroups: Transcontinental (A), Japanese (B), West African (C), and North African (D), on the basis of variations in the long terminal repeat (LTR). In Brazil, only a few studies have been done on HTLV-I diversity, usually using LTR sequencing data for subtyping (Segurado et al 2002).…”

Human T-lymphotropic virus 1aA circulation and risk factors for sexually transmitted infections in an Amazon geographic area with lowest human development index (Marajó Island, Northern Brazil)

“…Analyses conducted in HTLV-1 carriers in Brazil, both symptomatic (TSP/HAM) and asymptomatic, indicated that the prevalence of HTLV-1aA was greater than that of other viral subtypes and subgroups [43]. …”