Decreased Persistence of Maternal Antibodies in Infants Who Are HIV Exposed and Uninfected

Infants who are HIV exposed but uninfected (iHEU) are more susceptible to severe infections in the first months of life when compared with infants who are HIV unexposed. Previous studies showed an association with reduced transplacental transfer of maternal antibodies. Whether maternal HIV infection also affects the persistence of transferred maternal antibodies is unknown.

Serum samples were collected from 58 mother-infant pairs at delivery (maternal and cord blood) and at 1 month of age. A multiplex assay was established to test the levels of immunoglobulin G against tetanus, pertussis, cytomegalovirus, respiratory syncytial virus, and HIV.

When compared with infants who were HIV unexposed, iHEU had significantly lower antigen-specific antibody concentrations at 1 month across targeted pathogens, independent of maternal baselines and gestational ages. Impaired placental transfer and persistence of maternal antibodies contributed to the lower antibody levels in iHEU. Timing of antiretroviral therapy (ART) initiation in mothers had a profound impact on the dynamics of antibodies in iHEU. When compared with initiation of ART before pregnancy, iHEU whose mothers initiated ART during pregnancy had the lowest antibody concentrations at 1 month.

Our study shows that in addition to reduced placental transfer, maternal HIV infection is associated with reduced persistence of maternal antibodies after birth. This reduction could contribute to the increased susceptibility of iHEU to severe infections and supports the need to offer vaccination during pregnancy to women with HIV. Our data provide encouragement for screening of HIV infection and initiation of ART before pregnancy to enhance immunity transferred to iHEU.