Loss of detectable antibody to hepatitis B surface antigen in immunized patients with hemophilia but without human immunodeficiency virus infection

HBsAg as the antigen component of circulating immune complexes in HIV-infected patients

Seeing the same transmission pattern of HIV and HBV coinfection by these two agents is not an uncommon feature. Immunity impairment due to HIV infection can be the cause of a higher rate of HBV replication with less intensive liver damage and less effective immune response to HBV, while the pathological course in both infections involves elevated levels of circulating immune complexes (CIC). These were the reasons for us to examine the frequency of HBsAg involvement as the antigen component of circulating immune complexes formed in sera of HIV-infected patients in different stages of HIV disease. We tested 67 sera of HIV-positive patients in different stages of HIV disease for the presence of HBsAg and HIV antigen p24 (with and without acid dissociation of immune complexes), for the presence of anti-Hbc antibodies and circulating immune complexes. HBsAg was positive in 13.8% sera prior to and 33.8% after acid pretreatment. Anti-HBc antibodies were present in 76.9% serum samples tested. Fifty percent of sera were positive for both HBsAg and p24 antigen after dissociation of immune complexes. The level of CIC was elevated in 65.9% of sera. Our results suggest that HBsAg is commonly associated in immune complexes formed in the sera of HIV-infected patients and that they may simultaneously contain HIV and HBsAg in patients coinfected with both agents. This may contribute to their mutual interaction and influence the diagnosis and follow-up of patients.

Changes in hepatitis B serologic titers in HIV+ and HIV- children with haemophilia

This longitudinal study examines differences in hepatitis B immune titres in children and adolescents with haemophilia to determine if they are dependent on how immunity was acquired (vaccination or natural infection), and whether they are related to the child's HIV status and/or are influenced by HIV disease progression. Serologic titres (HBcAb, HBsAb) and HBsAg were measured prospectively at baseline, and at years 1, 2 and 3 of follow-up in 126 HIV- and 207 HIV+ children and adolescents with haemophilia. Analyses were performed to assess the impact of HIV status on the measured titres, and for HIV+ subjects to examine the association with CD4+ lymphocyte counts and p24 antigen status. The results show that HIV+ children were more likely than HIV- children to lose vaccine-induced immunity as indicated by the loss of HBsAb. There was an increased risk of losing HBsAb with higher CD4+ counts and younger age. Re-immunization was not successful in seven of eight HIV+ children. Two subjects (one HIV+, one HIV-) entered the study HBsAg- but became HBsAg+ over the course of follow-up. Seven HIV+ subjects lost natural immunity as indicated by the loss of HBcAb. The loss of either HBsAb or HBcAb in HIV--subjects was negligible to absent. In conclusion, because of the loss of immunity in HIV+ children the viral safety of factor replacement concentrates for these children is an important consideration. HIV- children rarely lose immunity, therefore frequent measures of HBsAb are not necessary.

Serial changes in titers of antibody to hepatitis B surface antigen after immunization of infants born to mothers with hepatitis B e antigen

To evaluate the long-term protection provided by hepatitis B (HB) vaccine in a high-risk environment, we followed 50 infants born to mothers with hepatitis B e (HBe) antigen. These infants were immunized with a three-dose regimen of plasma-derived HB vaccine and were followed for up to 10 years. Two infants (4%) acquired hepatitis B virus (HBV) infection before 1 year of age. The 48 other infants remained hepatitis B surface (HBs) antigen-negative during the follow-up period. The geometric mean titers of serum antibody to HBs antigen rapidly decreased during the first 4 years but remained at protective levels throughout the follow-up period. These data suggest that protection against significant HBV infection lasts for at least 10 years. We conclude that the long-term protection afforded by plasma-derived HB vaccine is satisfactory and that a routine booster dose before 10 years of age is not necessary.