RESUMEN
An anomalous high frequency of ATL was observed in a remote 'noir maroons' village of French Guiana. Since it is not clear if HTLV-I is responsible for different frequencies of disease in different geographical areas, we undertook a comparison of the population with a similar one located in Gabon. We found a much higher degree of gp46 surface envelope glycoprotein sequence conservation in the Guianese village than in the Gabonese one.
Asunto(s)
Variación Genética , Virus Linfotrópico T Tipo 1 Humano/genética , Leucemia-Linfoma de Células T del Adulto/virología , Secuencia de Bases , Secuencia Conservada , ADN Viral , Femenino , Guyana Francesa/epidemiología , Gabón/epidemiología , Productos del Gen env/genética , Humanos , Leucemia-Linfoma de Células T del Adulto/epidemiología , Masculino , Datos de Secuencia Molecular , Filogenia , Proteínas Oncogénicas de Retroviridae/genética , Alineación de SecuenciaRESUMEN
In order to gain new insights into the risk factors influencing human-T-cell-leukemia/lymphoma-virus-type-I (HTLV-I) mother-to-child transmission, a retrospective study of HTLV-I infection among children born to HTLV-I-seropositive women was carried out in a highly HTLV-I-endemic population of African origin living in French Guyana. The study covered 81 HTLV-I-seropositive mothers and their 216 children aged between 18 months old and 12 years old. All plasma samples were tested for the presence of HTLV-I antibodies by ELISA, immunofluorescence assay and Western blot. HTLV-I provirus was detected, in the DNA extracted from peripheral-blood mononuclear cells, by polymerase chain reaction (PCR) using primers specific for 3 different HTLV-I genomic regions (LTR, gag and pX) and quantified by a competitive PCR assay. Out of the 216 children, 21 were found to be HTLV-I-seropositive, giving a crude HTLV-I transmission rate of 9.7%, while among the 180 breast-fed children 10.6% were HTLV-I-seropositive. Perfect concordance between serological and PCR results was observed, and none of the 195 HTLV-I-negative children was found HTLV-I-positive by PCR. In conditional (by family) logistic-regression models, HTLV-I seropositivity in children was associated with an elevated maternal anti-HTLV-I-antibody titer (OR 2.2, p = 0.0013), a high maternal HTLV-I proviral load (OR 2.6, p = 0.033) and child's gender, girls being more frequently HTLV-I-infected than boys: OR 3.6, p = 0.0077 in the model including maternal anti-HTLV-I-antibody titer and OR 4.1, p = 0.002 in the model including the maternal HTLV-I proviral load.
Asunto(s)
Portador Sano/virología , Anticuerpos Anti-HTLV-I/sangre , Infecciones por HTLV-I/transmisión , Virus Linfotrópico T Tipo 1 Humano/aislamiento & purificación , Transmisión Vertical de Enfermedad Infecciosa , Complicaciones Infecciosas del Embarazo/virología , Lactancia Materna , Niño , Preescolar , ADN Viral/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Guyana Francesa , Genoma Viral , Infecciones por HTLV-I/sangre , Virus Linfotrópico T Tipo 1 Humano/genética , Humanos , Lactante , Recién Nacido , Masculino , Reacción en Cadena de la Polimerasa , Embarazo , Complicaciones Infecciosas del Embarazo/sangre , Provirus/genética , Provirus/aislamiento & purificación , Estudios Retrospectivos , Carga ViralRESUMEN
To determine the epidemiological characteristics of human T cell leukemia/lymphoma virus type I (HTLV-I) infection in the endemic village of Maripasoula, French Guiana, 1,614 persons (83.2% of the population) aged 2 to 91 years (mean age 21) were studied from November 1994 through April 1995. Plasma samples were screened by an HTLV-I ELISA and an IFA test (on MT2 cells), and positive samples were tested by an HTLV-I and -II type-specific Western blot. Overall seropositivity in the village was 6.7%, but HTLV-I infection was restricted to 3 of 6 ethnic groups, including the Noir-Marron (descendants of escaped African slaves, 8%), the Creoles (4.1%) and those of mixed Noir Marron/other ethnicity (3.6%). In the Noir-Marron population of 1,222 persons, including 606 men and 616 women and representing 76% of those tested, HTLV-I seroprevalence increased significantly with age in both sexes, reaching 40% in women older than 50 years. Univariate risk factors for HTLV-I seropositivity in women included older age, more pregnancies, more live births and a history of hospitalization. A cross-sectional analysis of sexual partners demonstrated an excess of discordant female HTLV-I+/male HTLV-I- couples, indicating preferential male-to-female sexual transmission. The demonstration of II HTLV-I-seropositive children aged less than 15 years, of whom 9 had a seropositive mother, suggested maternal-child HTLV-I transmission. Our results demonstrate a very high seroprevalence of HTLV-I in this South American population descended from African slaves, probably due to high rates of mother-to-child and sexual transmission within this rather isolated group.