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Background In Thailand where virtually all pregnant women are infected with HCMV, about 2% of infants are congenitally infected with HCMV. However, the transmission rate among infants born to HIV-1 infected mothers is not well known. Our objectives were to evaluate HCMV transmission rates in infants born to HIV-1 infected mothers, and to identify maternal and newborn risk factors associated with infant HCMV infection. Materials and methods Ninety-seven HIV-1 transmitting mothers were matched on maternal plasma HIV-1 RNA before zidovudine prophylaxis initiation with 194 non-transmitting mothers enrolled in PHPT-1, an HIV prevention trial in Thailand. Infant HCMV infection was assessed by anti-HCMV IgM and/or HCMV DNA within 6 months of age and by IgG serology at 18 months. Congenital HCMV infection was defined as the presence of HCMV IgM and/or a positive DNA PCR within 10 days of life. Univariate odds ratio (95% confidence intervals) were calculated for potential risk factors among maternal (age, HIV and immunological stage, pregnancy history, pregnancy complications, induction of labor, mode of delivery, past/present sexual transmitted diseases, CD4/CD8 T-lymphocyte counts) and infant characteristics (HIV status, sex, prematurity and birth weight). Adjusted odds ratios were calculated using logistic regression with stepwise selection of variables with less than 0.20 p value association. Results The prevalence of congenital HCMV infection was 16% (10/62) in HIV-1 infected infants and 5% (5/105) in uninfected infants, p=0.013. The prevalence of HCMV infection by 18 months of age was 83% (62/75) in HIV-1 infected infants and 62% (112/182) in uninfected infants, p=0.001. Upon univariate analysis, among the maternal factors, only vaginal delivery was associated with HCMV infection in infants (OR: 2.5; 95%CI: 1.3-4.7). Among infants' factors, HIV infection (OR: 3.3; 95%CI: 1.7-7.0) and prematurity (OR: 3.5; 95%CI: 1.0-18.8) were associated with HCMV. Upon multivariate analysis only vaginal delivery (OR: 2.5; 95%CI: 1.3-4.5) and infant HIV infection (OR: 3.3; 95%CI: 1.7-6.4) remained independently associated with HCMV infection in infants. Conclusions Infant HIV infection and vaginal delivery are the main risk factors for HCMV infection in children born to HIV-1 infected mothers. The clinical consequences of congenital and postnatal HCMV infection on HIV disease progression need to be assessed. [ABSTRACT FROM AUTHOR]

Abstract: Mother-to-child transmission (MTCT) of HIV-1 provides a model for studying the role of passively acquired antibodies in preventing HIV infection. We determined the titers of neutralizing antibodies (NAbs) against six primary isolates of clades B and CRF01_AE in sera from 45 transmitting and 45 nontransmitting mothers matched for the main independent factors associated with MTCT in Thailand. A lower risk of MTCT, particularly for intrapartum transmission, was associated only with higher NAb titers against the CRF01_AE strain, MBA. The envelope glycoprotein of this strain showed an unusually long V2 domain of 63 amino acids, encoding six potential N-linked glycosylation sites. We provided experimental data indicating that the extended V2 domain contributed to the higher level of resistance to neutralization by mothers'' sera in this strain. Taken together the data suggest that some primary isolates with specific properties may be useful indicators for identifying protective antibodies. [Copyright &y& Elsevier]