Mother-to-child transmission of HTLV-I : implication of high antiviral antibody titer and high proviral load in carrier mothers.

Abstract

P093 In order to gain new insight on the risk factors influencing 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 Guiana. Eighty-one HTLV-I seropositive mothers and their 216 children aged between 18 months old and 12 years old were included in the study. All plasma samples were tested for the presence of anti HTLV-I antibodies by ELISA, Immunofluorescence assay and Western Blot. HTLV-I provirus was detected, in the DNA extracted from PBMCs, by PCR using primers specific for 3 different HTLV-I genomic regions (LTR, gag and pX) and quantified by a competitive PCR assay. A perfect concordance between serological and PCR results was observed. None of the 195 HTLV-I negative children was found HTLV-I positive by PCR. Twenty-one children out of the 216 were found 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. 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).