Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region.

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Diagnosis of bone marrow necrosis.

Two cases of bone marrow necrosis (BMN) were diagnosed during life. Both patients developed BMN as a terminal event in the evolution of untreated malignant lymphoma. No earlier cases of BMN in untreated malignant lymphoma are reported in the literature. In one patient necrotic and normal bone marrow were simultaneously obtained from two different aspiration sites, showing the focal nature of the process. BMN itself being reversible, the diagnosis in vivo is important. A better knowledge of the significance of a yellow brown viscous fluid obtained by bone marrow aspiration and the exact interpretation of necrotic bone marrow films are essential to recognition of BMN.

Problems related to CPD preserved blood used for NEQAS trials in haematology.

A study of the results of the Belgian National External Quality Assessment Scheme (NEQAS) in haematology, revealed marked differences in MCV values obtained with instruments of different types. For this reason the citrate-phosphate-dextrose (CPD) preserved blood used as NEQAS material was analysed daily with a Coulter S-Plus IV and with a cross-calibrated Ortho ELT-800. The observed differences in MCV are apparently due to differences in measuring apparatus and also to the changing characteristics of the erythrocytes. Ageing of CPD blood during 1 to 4 days (postal delivery) influenced markedly the MCV as measured with the Ortho ELT systems. These time- and instrument-related factors influence the measurements, they interfere with the statistical evaluation of NEQAS results and can lead to errors in the evaluation of individual performers.