Vertically Acquired HIV Infection in Children Modulates Hepatitis B Surface Antigen Specific IgG Subclass Distribution After Early Childhood Vaccination Against Hepatitis B Virus Infection

Abstract

Pediatric vaccination against Hepatitis B Virus (HBV) leads to the induction of immunoglobulin G (IgG) antibodies specific to hepatitis B surface antigen (anti-HBs) consisting of four IgG subclasses. In the context of potential immuno-suppression arising from neonatal infection with the Immunodeficiency virus type one (HIV) an analyses of the anti-HBs response rate together with IgG subclass profiles especially in children vertically infected with HIV is of value in measuring the efficacy of childhood HBV vaccination. In this study we investigated in 50 HIV positive and 44 negative children the HBV vaccine response rate together with the profiles of IgG subclass responses specific to hepatitis B surface (HBsAg). The protective HBV vaccine response rate (antiHBs ≥10 mUI/ml) in the HIV infected children was 36% compared to 92 % in healthy controls. Whereas no difference was observed between the HIV positive and negative children with respect to IgM responses (P=0.99), a significant reduction in HBsAg specific IgG (P˂0.0001) and IgG subclass responses (P˂ 0.0001 for IgG1, P˂0.001 for IgG2, P<0.001 for IgG3 and P˂0.0001 for IgG4) was observed in HIV-1 infected children relative to their negative counterparts. Thus there is a significant reduction not only in the prevalence of sero-protective titer (anti-HBs ≥10mUI/ml) but equally in the IgG subclass responses specific to HBsAg amongst HIV-1 infected children. Both HIV positive and negative children showed minimal detectable levels of antibodies specific to the core protein (HBcAg) indicative low exposure to HBV. This was associated with elevated plasma levels of HBsAg specific IgG4 antibody responses probably indicating repeated exposure to the antigen. Our data highlights the necessity to monitor HBV vaccine responses in HIV infected children in Cameroon in order to revaccinate nonimmunized children.