Mother-to-child transmission of human T-cell-leukemia/lymphoma virus type I: Implication of high antiviral antibody titer and high proviral load in carrier mothers

In order to gain new insights into the risk factors influencing human-T-cel l-leukemia/lymphoma-virus-type-I (HTLV-I) mother-to child transmission, a r etrospective study of HTLV-I infection among children born to HTLV-I-seropo sitive women was carried out in a highly HTLV-I-endemic population of Afric an 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 E LISA, immunofluorescence assay and Western blot. HTLV-I provirus was detect ed, in the DNA extracted from peripheral-blood mononuclear cells, by polyme rase chain reaction (PCR) using primers specific for 3 different HTLV-I gen omic regions (LTR, gag and pX) and quantified by a competitive PCR assay. O ut of the 216 children, 21 were found to be HTLV-I-seropositive, giving a c rude HTLV-I transmission rate of 9.7%, while among the 180 breast-fed child ren 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-l-positive by PCR. In conditional (by family) logistic-regr ession models, HTLV-I seropositivity in children was associated with an ele vated maternal anti-HTLV-I-antibody titer (OR 2.2, p = 0.0013), a high mate rnal HTLV-I proviral load (OR 2.6, p = 0.033) and child's gender, girls bei ng more frequently HTLV-l-infected than boys: OR 3.6, p = 0.0077 in the mod el including maternal anti-HTLV-I-antibody titer and OR 4.1, p = 0.002 in t he model including the maternal HTLV-I proviral load. (C) 1999 Wiley-Liss, Inc.