Placental passage of antibodies to Dengue virus in persons living in a region of hyperendemic Dengue virus infection.

Maternal and umbilical cord levels of antibodies to dengue 2 and 3 viruses were compared in 54 matched pairs of specimens from subjects in the Dominican Republic. Dengue infection appeared to be hyperendemic; pregnant women experienced a 6% weekly infection rate. Titers of antibody to dengue 2 and 3 viruses were considerably higher in cord sera than in maternal sera (P smaller than 0.001 and P smaller 0.01, respectively), especially when maternal levels were low. When maternal and cord sera were compared at equal titers of dengue 2 virus, heterotypic antibodies to dengue 1 and St. Louis encephalitis viruses were higher in the cord. These findings could not be directly related to the higher levels of IgG found in cord sera or to the presence of elevated concentrations of IgM. It is concluded that antibody with increased cross-reactivity preferentially crosses the placenta. The presence of such cross-reactive antibody does not appear to sensitize infants to dengue hemorrhagic fever/shock syndrome.