Baseline epidemiological studies for a hepatitis B vaccine trial in Kangwane.

Hepatitis B markers were determined by radioimmunoassay of serum samples from 1 495 Black subjects representative of the resident population of Kangwane, a rural area with a high incidence of chronic liver disease and hepatocellular carcinoma. Pregnant women formed an important part of the study group, since it was intended to assess the frequency of perinatal transmission and the passive immunity of their infants, two factors which would markedly influence an infant immunization programme. A high overall marker positivity rate was found, indicating that hepatitis B is endemic. The hepatitis B surface antigen (HBsAg) carrier rate was 14,6% in adult males and 4,6% in adult females, while 82.6% of adult males and 69,4% of adult females were positive for at least one marker, indicating that infection had been present at some stage. Of infants under 1 year of age 34,5% were positive for antibodies to HBsAg (anti-HBs), compared with 9,3% at 13-24 months, which indicates that transplacental transfer of anti-HBs is frequent. Other markers were acquired even in the 1st year of life, with the sharpest increase at 3-11 years. Perinatal transmission was not common, however, and horizontal transmission during early childhood seemed to play an important role. It was concluded that the risk and frequency of infection justified a vaccine trial in this population and that the target group for vaccination should be infants under 1 year of age.

Radioimmunoassay of hepatitis B e-antigen (HBeAg): identification of HBeAg not associated with immunoglobulins.

A radioimmunoassay for hepatitis B e-antigen (HBeAg) is described. Polystyrene beads coated with IgG prepared from a human serum containing antibodies to HBeAg (anti-HBe) and anti-HBe IgG labelled with 125I-p-hydroxyphenylpropionic acid N-hydroxysuccinimide ester were used in the test. The radioimmunoassay was approximately 1,000-fold more sensitive than immunodiffusion. At least a transient presence of HBeAg in serum appears to be a common feature of infections by hepatitis B virus. The radioimmunoassay was instrumental in establishing conditions for identification of apparently free monomeric HBeAg. The HBeAg has an approximate mol. wt.of 35,000 and was recovered after isoelectric focusing in fractions with a pH between 4.25 and 4.8. Polyacrylamide gel electrophoresis revealed the presence in HBeAg of a polypeptide with an apparent mol. wt. of 17,000.

[Primary liver cancer and hepatitis B infection in Senegal. Comparison of cancer patients with 2 control groups]. / Cancer primitif du foie et infection par l'hépatite B au Sénégal. Comparaison des sujets cancéreux avec deux groupes témoins

A case/control study has been carried out to determine the prevalence of hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) in patients with primary liver cancer (PLC), and age/sex matched hospital controls with cancers of other sites (OCC) and similarly matched controls without cancer (NCC). HBsAg was found in 61.2% of 165 cases of PLC, as compared to 11.7% of 154 OCC and 11.3% of 328 NCC. The frequency of HBsAg in PLC patients was significantly higher (72.2%) in those with detectable alpha-fetoprotein as compared to those without (40.3%).

A case/control study of the association between primary liver cancer and hepatitis B infection in Senegal.

A case/control study has been carried out to determine by radioimmunoassay and passive hemagglutination techniques the prevalence of hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) in patients with primary liver cancer (PLC) and age/sex-matched hospital controls with cancers of other sites (OCC) and similarly matched controls without cancer (NCC). HBsAg was found in 61.2% of 165 cases of PLC as compared to 11.7% of 328 NCC. The frequency of HBsAg in PLC patients was significantly higher (72.2%) in those with detectable alpha fetoprotein as compared to those without (40.3%). There was no difference in the frequency of HBsAg in PLC patients with and without accompanying cirrhosis. No significant difference in potential hepatitis exposure history was found in the three study groups.