Eradicating hepatitis B virus: The critical role of preventing perinatal transmission.

Prevention of hepatitis B virus (HBV) transmission from infected mothers to their newborns is critical to HBV control and eventual eradication. Mother-to-child perinatal transmission causes the highest chronic carrier rate (>85%) with a high rate of subsequent chronic liver disease and hepatocellular carcinoma. This risk is reduced by 90% with HBV vaccine given along with hepatitis B immune globulin (HBIG) starting at birth. New analyses of our data from US trials of HBIG and HBV vaccine in high-risk infants revealed better efficacy with yeast-recombinant vaccine than plasma-derived vaccine, especially in preventing late onset infections, with evidence that vaccine prevented transmission of maternal HBV infection with the glycine to arginine mutation in surface antigen codon 145 (sG145R). Most late infections with sG145R were in vaccine non-responders, suggesting escape from HBIG rather than from vaccine-induced antibody. Our findings also help explain survey results from Taiwan following universal childhood immunization implemented in the mid-1980s. We conclude that current vaccines will remain effective against surface antigen mutants. Anti-viral drugs in high-risk pregnant women, in combination with newborn HBIG and vaccine, show promise for eliminating residual breakthrough neonatal infections, critical to meeting WHO 2030 goals and for eradicating HBV.

Multicenter evaluation of the Bayer VERSANT HIV-1 RNA 3.0 assay: analytical and clinical performance.

BACKGROUND: The use of quantitative HIV-1 RNA assays is part of the standard of care for the management of HIV-1-infected individuals. OBJECTIVE: The Bayer VERSANT HIV-1 RNA 3.0 Assay (bDNA) was evaluated for reproducibility, linearity, limits of detection and quantitation, effects of potentially interfering substances and conditions, effects of plasma collection and handling conditions, clinical sensitivity and specificity, and biologic variability. STUDY DESIGN: Anti-HIV-1-positive specimens, patient specimens containing potentially interfering substances, and anti-HIV-negative specimens were collected from several HIV clinics, blood centers, or commercial companies across the United States. Specimen panels used to evaluate nonclinical performance of the assay were prepared at Bayer Diagnostics. Bayer Assay Development personnel performed 2 of the nonclinical studies-effect of freeze-thaw cycles using 'spiked' HIV-1 RNA-positive samples and effect of other disease organisms. All other studies were conducted at 7 external sites. In some of the studies performed, specimens were tested in parallel with the Roche AMPLICOR HIV-1 MONITOR version 1.0 PCR Test. RESULTS/CONCLUSIONS: The results of these studies showed that the Bayer Assay has excellent reproducibility, a broad linear range (75-500,000 HIV-1 RNA copies/ml), throughput of 168 patient results per two-plate run in a 22-h period, and few limitations for use. Because this test is designed for use only in individuals who are known to be HIV-1-positive, the clinical specificity of 97.6% is adequate for its intended use. These characteristics make it an attractive method for general laboratory use of monitoring HIV-1-infected patients.

Genetic variation of hepatitis B surface antigen coding region among infants with chronic hepatitis B virus infection.

Variants in the amino acid composition of the primary antibody-binding site of hepatitis B surface antigen (HBsAg) have been identified in a number of populations with chronic hepatitis B virus (HBV) infection. Direct sequencing of amplified or cloned PCR products, solid phase detection of sequence-specific PCR products (SP-PCR), and limiting dilution cloning PCR (LDC-PCR) were compared to determine their sensitivity in detecting differing concentrations of HBsAg variants. LDC-PCR had the greatest sensitivity and could detect HBsAg variants at a concentration of 0.1% of the total viral population. HBsAg variants were detected in 51% of infants with chronic HBV infection acquired after postexposure prophylaxis, and more than half of the variants were detected only by the most sensitive methods.

Placental/umbilical cord blood for unrelated-donor bone marrow reconstitution: relevance of nucleated red blood cells.

Placental/umbilical cord blood (PCB) is a source of hematopoietic stem cells for bone marrow reconstitution. Engraftment speed and survival are related to the total nucleated cell (TNC) dose of the graft. This study explored the possible influence on engraftment of nucleated red blood cells (NRBCs) in the graft. Automated hematology analyzers were used to enumerate TNCs. NRBCs were counted by visual examination or by using an automated analyzer. Hematopoietic progenitor cells were enumerated as either colony-forming cells or CD34(+) cells. Transplant centers reported on transplant outcome in 1112 patients given PCB grafts through September 2001. NRBCs correlated with progenitor cell numbers. Both white blood cell and NRBC dose were independently predictive of myeloid engraftment speed. Because NRBC dose predicted engraftment speed, inclusion of NRBCs in the TNC count does not reduce the effectiveness of the prefreezing TNC count as an index of the quality of a PCB unit as a graft. The correlation between the number of NRBCs and the number of hematopoietic progenitor cells probably reflects the involvement of early stem cells in erythroid responses.