HIV-1 Is Associated with Lower Group B Streptococcus Capsular and Surface-Protein IgG Antibody Levels and Reduced Transplacental Antibody Transfer in Pregnant Women

Background. Human immunodeficiency virus (HIV)-exposed infants are at increased risk of invasive Group B Streptococcus (GBS) disease; however, the reason for this increased susceptibility has not been characterized. Methods. We compared GBS capsular and surface-protein maternal immunoglobin G antibody concentrations and cord-maternal ratios between HIV-infected and HIV-uninfected mother-newborn dyads. Results. Median capsular antibody concentrations (μg/mL) were lower in HIV-infected than HIV-uninfected women for serotypes Ib (P =. 033) and V (P =. 040); and for pilus island (PI)-1 (P =. 016), PI-2a (P =. 015), PI-2b (P =. 015), and fibrinogen-binding protein A (P <. 001). For serotypes Ia and III, cord-maternal ratios were 37.4% (P <. 001) and 32.5% (P =. 027) lower in HIV-infected compared to HIV-uninfected mother-newborn dyads. The adjusted odds of having capsular antibody concentration ≥2 μg/mL when comparing HIV-infected to -uninfected women were 0.33 (95% confidence interval [CI],. 15-.75) and 0.34 (95% CI,. 12-1.00) for serotypes Ia and III, respectively. Antibody levels and cord-maternal ratios were independent of CD4+ lymphocyte counts or HIV-1 viral load. Conclusions. The lower GBS antibody concentrations and reduced transplacental antibody transfer in HIV-infected women, which likely contribute to their infants being at heightened susceptibility for invasive GBS disease, could possibly be mitigated by vaccination with a GBS conjugate vaccine currently under clinical development.