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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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Release of hormones induce immune suppression and fetal tolerance during pregnancy.
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Figure 2: Release of hormones induce immune suppression and fetal tolerance during pregnancy.

Mentions: Progesterone, a hormone associated with the maintenance of pregnancy, is immunosuppressive and decreases NK cell cytotoxicity, inhibits nitric oxide (NO) and tumour necrosis factor (TNF)-α production. Progesterone induced binding factor inhibits the activity of dendritic cells (DCs) that generate proinflammatory responses and favour the induction of tolerogenic DCs. It also controls the activity of natural killer (NK) cells and the differentiation of T cells into T helper cell type 2 (Th2) like clones (Fig. 2). Therefore, progesterone mediates the immunological effects, and induces the production of Th2 dominant cytokines like IL-3, IL-4, and IL-1055 (Fig. 2). The Th2 phenotype induced by progesterone is a prerequisite for the maintenance of pregnancy, which is associated with the susceptibility and the existing disease exacerbation5657. The anti-inflammatory properties of progesterone prevent the development of Th1 responses that could result in foetal abortion58.


Immunological mechanisms of hepatitis B virus persistence in newborns.

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

Release of hormones induce immune suppression and fetal tolerance during pregnancy.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Release of hormones induce immune suppression and fetal tolerance during pregnancy.
Mentions: Progesterone, a hormone associated with the maintenance of pregnancy, is immunosuppressive and decreases NK cell cytotoxicity, inhibits nitric oxide (NO) and tumour necrosis factor (TNF)-α production. Progesterone induced binding factor inhibits the activity of dendritic cells (DCs) that generate proinflammatory responses and favour the induction of tolerogenic DCs. It also controls the activity of natural killer (NK) cells and the differentiation of T cells into T helper cell type 2 (Th2) like clones (Fig. 2). Therefore, progesterone mediates the immunological effects, and induces the production of Th2 dominant cytokines like IL-3, IL-4, and IL-1055 (Fig. 2). The Th2 phenotype induced by progesterone is a prerequisite for the maintenance of pregnancy, which is associated with the susceptibility and the existing disease exacerbation5657. The anti-inflammatory properties of progesterone prevent the development of Th1 responses that could result in foetal abortion58.

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