The importance of cytomegalovirus-specific antibodies for the prevention of fetal cytomegalovirus infection or disease.

Primary maternal infection with cytomegalovirus (CMV) during or just before pregnancy is responsible for nearly all congenital infections where the baby is symptomatic at birth. If primary maternal CMV infection occurs during the first or second trimester, between one-third and one-half of fetuses become infected, and between one-half and one-third of infected fetuses go on to have symptoms at birth. Experiments using a guinea-pig model of CMV infection in pregnant dames (and subsequent observational studies in humans) indicate a beneficial effect is associated with administering high-titre CMV hyperimmunoglobulin (HIg) to pregnant women with primary CMV infection. HIg appears to be effective for treating and preventing fetal CMV infection; its mechanism of action probably includes reduced placental inflammation, viral neutralization associated with high-avidity antibodies and, possibly, downregulation of cytokine-mediated cellular immune responses.