Role of human cytomegalovirus (HCMV)-specific antibody in HCMV-infected pregnant women.

Maternal preconception immunity confers substantial protection against HCMV infection and disease to the unborn child. However, the protective role played by single components of virus-specific humoral and cellular immunity is poorly defined. Recently, it was discovered that UL128-131 gene products are essential for the virus to exert endothelial/epithelial cell tropism during natural infection. This, together with the finding that the gH-gL-UL128-131 complex can elicit early, highly potent, and long-lasting neutralizing antibody response as well as other antibodies involved in cell-to-cell spreading and virus transfer from endothelial cells to leukocytes, indicate that antibodies may indeed potentially control virus dissemination in vivo and play a role in mother-to-fetus transmission as well. Additionally, passive immunization of pregnant women with primary HCMV infection has been reported to be highly beneficial for both prevention and therapy of congenital infection in nonrandomized studies. Recently, a phase IIB, randomized, double blind, hyperimmunoglobulin vs placebo trial (CHIP study) showed a lower, although not significant, rate of transmission in the hyperimmunoglobulin arm. Ongoing phase III controlled trials as well as laboratory investigations will hopefully help in better defining the protective role of maternal antibodies.