Little is known about the vaccine protective response for infants born from HIV-infected mothers. We evaluated the antibody response to hepatitis B, tetanus, and diphtheria vaccine in vertically HIV-exposed uninfected infants and compared them to those of control infants not exposed to the virus. The quantitative determination of specific neutralizing antibodies against hepatitis B, diphtheria, and tetanus were performed blindly on serum samples. The results showed that 6.7% of the HIV-exposed uninfected individuals were nonresponders to hepatitis B vaccine (anti-HBs titer, <10 mIU/ml), and 64.4% were very good responders (anti-HBs titer, >1,000 mIU/ml), whereas only 3.6% of the nonexposed infants were nonresponders ( 2 ‫؍‬ 10.93; 1 df). The HIV-exposed uninfected infants showed protective titers for diphtheria and tetanus but lower geometric mean anti-tetanus titers compared to those of the HIV-unexposed infants. Our data point to the necessity of evaluating vaccine immune responses in these children and reinforced that alterations in lymphocyte numbers and functions reported for newborns from HIV-infected mothers interfere with the vaccine response.

BCG-specific T-cell proliferation was reduced in HIV-exposed uninfected infants and IFN-γ concentration was lower in younger exposed infants, showing a delay in immune system maturation of HIV-exposed infants.

Gamma interferon, tumor necrosis factor alpha, interleukin-4 (IL-4), and IL-10 levels in supernatants and serum anti-PT IgG levels were determined using enzyme-linked immunosorbent assay (ELISA). The net percentage of CD3؉ blasts in cultures with B. pertussis in the group vaccinated with wP was higher than that in the group vaccinated with the wP low vaccine (medians of 6.2% for the wP vaccine and 3.9% for the wP low vaccine; P ‫؍‬ 0.029). The frequencies of proliferating CD4 ؉ , CD8 ؉ , and ␥␦ ؉ cells, cytokine concentrations in supernatants, and the geometric mean titers of anti-PT IgG were similar for the two vaccination groups. There was a significant difference between the T-cell subpopulations for B. pertussis and PHA cultures, with a higher percentage of ␥␦ ؉ cells in the B. pertussis cultures (P < 0.001). The overall data did suggest that wP vaccination resulted in modestly better specific CD3 ؉ cell proliferation, and ␥␦ ؉ cell expansions were similar with the two vaccines.