Intrauterine transmission of cytomegalovirus to infants of women with preconceptional immunity.

Background: Preconceptional immunity against cytomegalovirus (CMV) provides only partial protection against intrauterine transmission of the virus. Wh ether congenital CMV infection in the offspring of women who are seropositi ve for CMV can occur after maternal reinfection with a different strain of CMV is unknown. Methods: Serum specimens from 46 women with preconceptional immunity agains t CMV that were obtained during the previous pregnancy and the current preg nancy were analyzed for antibodies against the strain-specific epitopes of CMV glycoprotein H. Virus-neutralizing activity in maternal serum samples w as measured against the AD169 laboratory strain of CMV and the CMV isolates available from seven infected infants. In addition, the nucleotide sequenc es of the glycoprotein H gene from the seven CMV isolates were determined. Results: Eleven of the 16 mothers with infected infants (69 percent) had an tibodies against the glycoprotein H epitopes present on two laboratory stra ins of CMV, AD169 and Towne. Ten of the 16 mothers with infected children ( 62 percent) acquired new antibody specificities against glycoprotein H, as compared with only 4 of the 30 mothers of uninfected infants (13 percent, P <0.001). The samples obtained at the time of the current delivery from four of the seven mothers contained at least twice as many neutralizing antibod ies against the CMV isolated from their infants as were present in the samp les obtained at the previous delivery. The specificity of the newly acquire d maternal antibodies reflected the amino acid sequence of the glycoprotein H epitope of CMV from these four infants. Conclusions: In women who are seropositive for CMV, reinfection with a diff erent strain of CMV can lead to intrauterine transmission and symptomatic c ongenital infection. (N Engl J Med 2001;344:1366-71.) Copyright (C) 2001 Ma ssachusetts Medical Society.