Congenital human cytomegalovirus infection is associated with decreased transplacental IgG transfer efficiency due to maternal hypergammaglobulinemia.

Overview

abstract

BACKGROUND: Placentally-transferred maternal IgG protects against pathogens in early life, yet vertically-transmitted infections can interfere with transplacental IgG transfer. Although human cytomegalovirus (HCMV) is the most common placentally-transmitted viral infection worldwide, the impact of congenital HCMV (cCMV) infection on transplacental IgG transfer has been underexplored. METHODS: We evaluated total and antigen-specific maternal and cord blood IgG levels and transplacental IgG transfer efficiency in a U.S-based cohort of 93 mother-infant pairs including 27 cCMV-infected and 66 cCMV-uninfected pairs, of which 29 infants were born to HCMV-seropositive non-transmitting mothers and 37 to HCMV-seronegative mothers. Controls were matched on sex, race/ethnicity, maternal age, and delivery year. RESULTS: Transplacental IgG transfer efficiency was decreased by 23% (95% CI 10-36%, p=0.0079) in cCMV-infected pairs and 75% of this effect (95% CI 28-174%, p=0.0085) was mediated by elevated maternal IgG levels (i.e., hypergammaglobulinemia) in HCMV-transmitting women. Despite reduced transfer efficiency, IgG levels were similar in cord blood from infants with and without cCMV infection. CONCLUSIONS: Our results indicate that cCMV infection moderately reduces transplacental IgG transfer efficiency due to maternal hypergammaglobulinemia; however, infants with and without cCMV infection had similar antigen-specific IgG levels, suggesting comparable protection from maternal IgG acquired via transplacental transfer.