Hepatitis B and C in children

HBV Seroprotection and Anamnestic Response to Booster Vaccination in Pediatric Cancer Survivors

Hepatitis B is a major global health concern and can be prevented in the era of vaccination. Impaired immunological memory to primary immunization is a common chemotherapy-related complication among cancer survivors. The study aimed to determine protective immunity against hepatitis B virus (HBV) and anamnestic response to booster vaccination. In all, 107 pediatric cancer survivors previously immunized with primary hepatitis B vaccination were enrolled. A hepatitis B booster dose was administered to those with suboptimal seroprotection (anti-HBs < 10 mIU/mL) and 2 additional doses were subsequently administered at 1 and 6 months to those whose anti-HBs remained low. Clinical and serologic parameters were analyzed. Sero-protective rate against HBV (anti-HBs ≥ 10 mIU/mL) among survivors was 20.6% with geometric mean titer (GMT) of 95.7 ± 265.6 mIU/mL. Anamnestic response was 61% after a booster vaccine among those with suboptimal seroprotection and 100% after 2 additional booster doses among those whose anti-HBs remained low. GMTs among those survivors after the First and third booster vaccines were 320.0 ± 412.4 mIU/mL and 826.5 ± 343.8 mIU/mL, respectively. Age at diagnosis was a significant independent risk factor for adequate seroprotection (adjusted OR = 0.84, 95%CI: 0.71-0.99) with a P-value of .034. No associated risk factors to predict optimal anamnestic response to booster vaccination were identified. Loss of immunological memory to primary hepatitis B immunization is an inevitable complication among most pediatric cancer survivors; therefore, assessing adequate seroprotection is essentially required. For those with limited accessibility to serologic tests, completion of full 3-booster-dose series is alternative and highly recommended.

Hepatitis B and C

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections represent a major global public health and economic burden, with an estimated 257 million and 71 million people, respectively, having chronic infection worldwide. The natural history of HBV and HCV in children depends on age at time of infection, mode of acquisition, ethnicity, and genotype. Most children infected perinatally or vertically remain asymptomatic but are at uniquely higher risk of developing chronic viral hepatitis, progressing to liver cirrhosis and hepatocellular carcinoma (HCC), hence classifying HBV and HCV as oncoviruses. This article discusses the epidemiology, virology, immunobiology, prevention, clinical manifestations, evaluation, and the advances in treatment of hepatitis B and C in children.

Cost-effectiveness analysis of preventing mother-to-child transmission of hepatitis B by injecting hepatitis B immune globulin

OBJECTIVE

Hepatitis B immune globulin (HBIG) injection during pregnancy and/or after birth is an intervention for preventing mother-to-child transmission of the hepatitis B (HB) virus. However, varying cost-effectiveness ratios among various HBIG therapies remain unclear. This study explored these differences in cost-effectiveness ratios.

METHODS

Four districts in Wuhan, China, were selected for the current study using stratified random sampling. Pregnant women who were positive for HB surface antigen (HBsAg) and who received prenatal care in district-level maternal and child health hospitals were interviewed. The mothers and their children underwent follow-up visits from the time of pregnancy until the children were six-and-a-half months old.

RESULTS

A total of 324 cases completed the follow-up visits on a voluntary basis. Among the 324 HBsAg-positive pregnant women investigated, 60.49% (196/324) were injected with HBIG at different trimesters. A total of 249 neonates (76.85%) received an HBIG injection within 24 h after birth. The HBsAg-positive rate in infants was 5.56% (18/324). The HBIG-injected mother and infant group had the lowest chronic infection rate among children [odds ratio=0.14, 95% confidence interval (CI) 0.02-0.90, P=0.039]. The HBIG-injected infant group exhibited the lowest HBsAb-positive rate (odds ratio=0.07, 95% CI 0.02-0.23). The cost per averted disability-adjusted life years was lowest in the infant group: USD 118.61 (95% CI 105.23-131.99).

CONCLUSION

These results indicate that active and passive immunizations (HBIG and HB vaccine) entail the lowest cost in the prevention of chronic HB infection in infants. However, this programme has the lowest HBsAb-positive rate, which possibly prevents children from self-acquiring antibodies.

An overview: in vitro models of HCV replication in different cell cultures

Although much of productive research has been conducted in the field of molecular virology of Hepatitis C virus (HCV) regarding its genes, gene functions and proteins, development of an efficient cell culture model for its replication remained a focused area. Focus has been directed to establish HCV in vitro replication system. This replication system should mimic its intrahepatic pathogenesis so that antivirals should be screened and in vitro gene profiling of HCV induced pathogenesis should be worked out. Since 1990 various experimental approaches and strategies have been utilized in phase of development of a robust replication model for HCV, and success has been reported for a few genotypes. Still the work is going on to have more success in availing such robust replication models for all the genotypes. This will help to have a common antiviral strategy against HCV induced pathogenesis involving any genotype or subtype.

Genetic variation in interleukin 28B with respect to vertical transmission of hepatitis C virus and spontaneous clearance in HCV-infected children

The vertical transmission of hepatitis C virus (HCV-VT) is a major route of HCV infection in children, but the risk factors remain incompletely understood. This study analyzed the role of interleukin 28B (IL28B) in HCV-VT and in the spontaneous clearance of HCV among infected infants. Between 1991 and 2009, 145 mothers were recruited for this study: 100 were HCV-RNA+ve / human immunodeficiency virus negative (HIV-ve), with 128 children, and 33 were HCV-RNA-ve/HCV antibody+ve, with 43 children. The infants were tested for HCV-RNA at birth and at regular intervals until the age of 6 years. IL28B (single nucleotide polymorphism rs12979860) was determined in the mothers and children. HCV-VT was assumed when children presented HCV-RNA+ve in two subsequent blood samples. HCV-VT-infected infants were categorized as: (1) transient viremia with posterior HCV-RNA-ve and without serum-conversion; (2) persistent infection with serum-conversion. Of the 31 mothers with CC polymorphism, 19 (61%) were HCV-RNA+ve, whereas among the 68 mothers with non-CC polymorphism, 56 (82%) were HCV-RNA+ve. In all, 26 of 128 (20%) infants born to the HCV-RNA+ve mothers acquired HCV infection, but only 9 (7%) were chronically infected. The rate of HCV-VT was higher among the mothers with higher HCV viremia. No HCV-VT was detected in the HCV-RNA-ve women. Neither the mothers' nor the childrens' IL-28 status was associated with an increased risk of HCV-VT. The factors influencing viral clearance among the infected children were genotype non-1 and genotype CC of IL28B. In logistic regression, child CC polymorphism was the only predictor of HCV-clearance in HCV genotype-1.

CONCLUSION

High maternal viral load is the only predictive factor of HCV-VT. IL28B plays no role in HCV-VT, but IL28B CC child polymorphism is associated independently with the spontaneous clearance of HCV genotype-1 among infected children.

Generation of cellular immune responses to HCV NS5 protein through in vivo activation of dendritic cells

Chronic hepatitis C (HCV) infection is a substantial medical problem that leads to progressive liver disease, cirrhosis, and hepatocellular carcinoma (HCC). The aim of this study was to achieve sustained cellular immune responses in vivo to a HCV nonstructural protein using dendritic cell (DC)-based immunization approach. We targeted the HCV NS5 protein to DCs in vivo by injecting microparticles loaded with this antigen. The DC population was expanded in BALB/C mice (H-2(d) ) by hydrodynamic injection of a plasmid pUMVC3-hFLex expressing the secreted portion of the human Fms-like tyrosine kinase receptor-3 ligand (hFlt3). Mice were subsequently injected with microparticles coated with HCV NS5 protein via the tail vein. Cellular immune responses were determined with respect to secretion of INFγ and IL2 by CD4(+) cells and cytotoxic T-lymphocyte (CTL) assays in vitro; inhibition of tumour cell growth was employed for the assessment of CD8(+) generated activity in vivo. We found that Flt3L treatment expanded the DC population in the spleen to 43%, and such cells displayed a striking upregulation of CD86 as well as CD80 and CD40 co-stimulating molecules. Viral antigen-specific T(H) 1 cytokine secretion by splenocytes was generated, and CTL activity against syngeneic NS5 expressing myeloma target cells was observed. In addition, these cells inhibited tumour growth indicating that NS5-specific robust CTL activity was operative in vivo. Thus, the capability of activating DCs in vivo using the methods described is valuable as a therapeutic vaccine strategy for chronic HCV infection.

Stem/progenitor cells in liver injury repair and regeneration

Morbidity and mortality from cirrhosis is increasing rapidly in the world. Currently, orthotopic liver transplantation is the only definitive therapeutic option. However, its clinical use is limited, because of poor long-term graft survival, donor organ shortage and high costs associated with the procedure. Stem cell replacement strategies are therefore being investigated as an attractive alternative approach to liver repair and regeneration. In this review we discuss recent preclinical and clinical investigations that explore the therapeutic potential of stem cells in repair of liver injuries. Several types of stem cells. including embryonic stem cells, haematopoietic stem cells and mesenchymal stem cells, can be induced to differentiate into hepatocyte-like cells by defined culture conditions in vitro. Stem cell transplantation has been shown to significantly improve liver function and increase animal survival in experimentally-induced liver-injury models. Moreover, several pilot clinical studies have reported encouraging therapeutic effects in patients treated with stem cells. Although there remain many unresolved issues, the available data support the notion that stem cell technology may lead to the development of effective clinical modalities for human liver diseases.