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Immunological mechanisms of hepatitis B virus persistence in newborns.

Trehanpati N, Hissar S, Shrivastav S, Sarin SK - Indian J. Med. Res. (2013)

Bottom Line: T cell receptor (TCRζ) chain defects were also associated with decreased CD8 T cell dysfunction.Decreased TCRζ expression could be due to persistent intrauterine exposure of the viral antigens early in embryonic development leading to immune tolerance to HBV antigens in the newborns positive for hepatitis B surface antigen (HBsAg+ve).However, HBV vaccination may have benefits in restoring acquired immunity and better production of HBV specific antibodies.

View Article: PubMed Central - PubMed

Affiliation: Department of Research, Institute of Liver & Biliary Sciences, New Delhi, India.

ABSTRACT
Chronic hepatitis B virus (HBV) infection affects millions of people worldwide and about a half million people die every year. India represents the second largest pool of chronic HBV infection worldwide with an estimated 40 million infected people. The prevalence of chronic HBV infection in pregnant women is shown to be 0.82 per cent with the risk of mother-to-child vertical transmission. Hepatitis B e antigen (HBeAg) positivity indicates replicative form of HBV which may play a role in immunotolerance in utero by crossing the placenta. In case of HBeAg positivity and high viral load of mother, HBV immunoglobulin is preferably given along with HBV vaccination. Antiviral therapy is recommended for use in the third trimester of pregnancy to reduce the perinatal transmission of HBV, however, use of antiviral therapy should be individualized during pregnancy. Chronic HBV infection in neonates is linked with strong presence of Tregs (T regulatory cells) and defective CD8 T cells pool to produce interferon (IFN)-γ. T cell receptor (TCRζ) chain defects were also associated with decreased CD8 T cell dysfunction. Decreased TCRζ expression could be due to persistent intrauterine exposure of the viral antigens early in embryonic development leading to immune tolerance to HBV antigens in the newborns positive for hepatitis B surface antigen (HBsAg+ve). Therefore, due to HBV infection, T cell tolerance to HBV-antigen may probably leave the newborn as a chronic carrier. However, HBV vaccination may have benefits in restoring acquired immunity and better production of HBV specific antibodies.

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Secretory proteins crossing the placenta and vertical transmission through during and after delivery.
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Figure 1: Secretory proteins crossing the placenta and vertical transmission through during and after delivery.

Mentions: Of the two secretory proteins; HBsAg and HBeAg, HBsAg does not usually cross the placenta, however, small sized HBeAg passes through the placental barrier even with low maternal viral load titre1213 (Fig. 1). In newborn, transplacental HBeAg can be detected at one month of age but it would disappear before 4 months of age. However, in a few, infected newborns with HBV viral titres, persistent detection of HBeAg for more than 4 months strongly indicates HBV chronicity1415. It is also observed that anti-HBc (antibodies to core antigen) positivity can be detected more than anti-HBe in the babies born to hepatitis B infected mothers1213. Therefore, anti-HBe till one year of age and anti-HBc till two years of age represent the transplacental maternal antibodies to the virus, and may not be an indicator of present active or past HBV infection in babies born to hepatitis B infected mothers.


Immunological mechanisms of hepatitis B virus persistence in newborns.

Trehanpati N, Hissar S, Shrivastav S, Sarin SK - Indian J. Med. Res. (2013)

Secretory proteins crossing the placenta and vertical transmission through during and after delivery.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928700&req=5

Figure 1: Secretory proteins crossing the placenta and vertical transmission through during and after delivery.
Mentions: Of the two secretory proteins; HBsAg and HBeAg, HBsAg does not usually cross the placenta, however, small sized HBeAg passes through the placental barrier even with low maternal viral load titre1213 (Fig. 1). In newborn, transplacental HBeAg can be detected at one month of age but it would disappear before 4 months of age. However, in a few, infected newborns with HBV viral titres, persistent detection of HBeAg for more than 4 months strongly indicates HBV chronicity1415. It is also observed that anti-HBc (antibodies to core antigen) positivity can be detected more than anti-HBe in the babies born to hepatitis B infected mothers1213. Therefore, anti-HBe till one year of age and anti-HBc till two years of age represent the transplacental maternal antibodies to the virus, and may not be an indicator of present active or past HBV infection in babies born to hepatitis B infected mothers.

Bottom Line: T cell receptor (TCRζ) chain defects were also associated with decreased CD8 T cell dysfunction.Decreased TCRζ expression could be due to persistent intrauterine exposure of the viral antigens early in embryonic development leading to immune tolerance to HBV antigens in the newborns positive for hepatitis B surface antigen (HBsAg+ve).However, HBV vaccination may have benefits in restoring acquired immunity and better production of HBV specific antibodies.

View Article: PubMed Central - PubMed

Affiliation: Department of Research, Institute of Liver & Biliary Sciences, New Delhi, India.

ABSTRACT
Chronic hepatitis B virus (HBV) infection affects millions of people worldwide and about a half million people die every year. India represents the second largest pool of chronic HBV infection worldwide with an estimated 40 million infected people. The prevalence of chronic HBV infection in pregnant women is shown to be 0.82 per cent with the risk of mother-to-child vertical transmission. Hepatitis B e antigen (HBeAg) positivity indicates replicative form of HBV which may play a role in immunotolerance in utero by crossing the placenta. In case of HBeAg positivity and high viral load of mother, HBV immunoglobulin is preferably given along with HBV vaccination. Antiviral therapy is recommended for use in the third trimester of pregnancy to reduce the perinatal transmission of HBV, however, use of antiviral therapy should be individualized during pregnancy. Chronic HBV infection in neonates is linked with strong presence of Tregs (T regulatory cells) and defective CD8 T cells pool to produce interferon (IFN)-γ. T cell receptor (TCRζ) chain defects were also associated with decreased CD8 T cell dysfunction. Decreased TCRζ expression could be due to persistent intrauterine exposure of the viral antigens early in embryonic development leading to immune tolerance to HBV antigens in the newborns positive for hepatitis B surface antigen (HBsAg+ve). Therefore, due to HBV infection, T cell tolerance to HBV-antigen may probably leave the newborn as a chronic carrier. However, HBV vaccination may have benefits in restoring acquired immunity and better production of HBV specific antibodies.

Show MeSH
Related in: MedlinePlus