Soroepidemiologia e caracterização molecular da infecção pelo Vírus linfotrópico de células T humanas 1 e 2 (HTLV-1/2) em mulheres gestantes na cidade de Belém, Pará

Abstract

HTLV-1/2 infection was already investigated in several populations, showing variable prevalence according to the geographical area, ethnic groups and analyzed subpopulations. In Brazilian studies a larger prevalence was observed in the States of Bahia and Pará. The present study aimed to evaluate the prevalence of HTLV in pregnant women in the Belém city, Pará, through sorologics and molecular assays. One thousand and twnty-seven (1.027) blood samples were collected and plasma aliquots were tested for the presence of antibodies anti-HTLV-1/2, using enzyme immunoassay ELISA (Ortho Diagnostic Systems Inc., USA). The confirmation of the infection and types and subtypes differentiation was determined by a Nested Polimerase Chain Reaction (Nested PCR) targeting the pX, env and 5'LTR regions followed by RFLP analysis and sequencing of the products amplified. It were detected six (0,59%) cases of serorreactivity for anti-HTLV that were confirmed by the amplification of a 159 pb fragment from the pX region. The RFLP analysis with the enzyme TaqI showed that four (66,7%) samples were positive for HTLV-1 and two (33,3%) for HTLV-2. One out of the HTLV-2 samples had a fragment of 630 pb of the env gene amplified. The analysis with the endonuclease XhoI showed the presence of a profile characteristic of the HTLV-2a/2c subtypes. Two samples HTLV-1 and one HTLV-2 had the 5'LTR region amplified and sequenced. The phylogenetic analysis classified the samples HTLV-1 as Cosmopolitan subtype, subgroup Transcontinental and HTLV-2 as belonging to the HTLV-2c subtype. That study shows the relevance of introducing the test for HTLV in the prenatal selection, in order to reduce vertical and horizontal transmission in our State.