Paediatrics: Children need optimal management of chronic hepatitis B

Prevention of Hepatitis B Virus Infection and Liver Cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population starting from birth dose, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective, the cancer preventive efficacy support it as the first successful example of cancer preventive vaccine in human. Addition of hepatitis B immunoglobulin immediately after birth and antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are existing or possible emerging strategies to enhance the prevention efficacy of HBV infection and its related liver cancer. Secondary prevention with current antiviral agents may reduce the risk or delay the onset of HCC development, but could not eradicate HBV infection and HCC. Better antiviral therapeutic agents are needed for better secondary prevention.

Entecavir Treatment in Children and Adolescents with Chronic Hepatitis B Virus Infection

BACKGROUND

The aim of this study was to investigate the treatment response of entecavir (ETV) in children and adolescents with chronic hepatitis B (CHB) who acquired infection perinatally or during early childhood.

METHODS

A total of nine treatment-naïve patients [median aged 12.2 years (range: 2.6-18.0); five girls and four boys], with hepatitis B e antigen (HBeAg) seropositive > 6 months, alanine aminotransferase (ALT) > 2 times of upper limit of normal value (30 IU/L), were enrolled for ETV therapy. They received ETV therapy with a dose of 0.015 mg/kg/d, with a maximal dose of 0.5 mg daily for at least 52 weeks. Another 27 untreated CHB patients matched for age, sex, ALT levels, and HBeAg status were recruited as the control group. A complete response at 48-52 weeks was defined as follows: (1) normalization of ALT; (2) undetectable hepatitis B virus DNA; and (3) HBeAg/anti-HBe seroconversion. All 36 patients were retrospectively reviewed for their biochemical, serological, and virologic responses.

RESULTS

ETV-treated patients achieved rapid ALT normalization (all before 8 months of treatment) compared with the control group (p < 0.001) and they had a greater chance of achieving undetectable HBV DNA levels at Week 52 after treatment (55.6% vs. 11.1%, p = 0.013). The cumulative incidence rates of HBeAg seroconversion were similarly high in both groups (ETV group 44% at 1 year 78% at 2 years; control group 37% at 1 year 63% at 2 years, respectively). The ETV group also had a trend of better complete response than the control group (22.2% vs. 0%, p = 0.057). None of the ETV-treated patients reported significant adverse effects.

CONCLUSION

Entecavir for pediatric CHB treatment is safe and shows clinical benefits in short-term biochemical and virologic responses. Further studies to determine long-term remission and drug resistance are required.

Efficacy of maternal tenofovir disoproxil fumarate in interrupting mother-to-infant transmission of hepatitis B virus

The efficacy and safety of maternal tenofovir disoproxil fumarate (TDF) in reducing mother-to-infant hepatitis B virus (HBV) transmissions is not clearly understood. We conducted a prospective, multicenter trial and enrolled 118 hepatitis B surface antigen (HBsAg)- and hepatitis B e antigen-positive pregnant women with HBV DNA ≥7.5 log10 IU/mL. The mothers received no medication (control group, n = 56, HBV DNA 8.22 ± 0.39 log10 IU/mL) or TDF 300 mg daily (TDF group, n = 62, HBV DNA 8.18 ± 0.47 log10 IU/mL) from 30-32 weeks of gestation until 1 month postpartum. Primary outcome was infant HBsAg at 6 months old. At delivery, the TDF group had lower maternal HBV DNA levels (4.29 ± 0.93 versus 8.10 ± 0.56 log10 IU/mL, P < 0.0001). Of the 121/123 newborns, the TDF group had lower rates of HBV DNA positivity at birth (6.15% versus 31.48%, P = 0.0003) and HBsAg positivity at 6 months old (1.54% versus 10.71%, P = 0.0481). Multivariate analysis revealed that the TDF group had lower risk (odds ratio = 0.10, P = 0.0434) and amniocentesis was associated with higher risk (odds ratio 6.82, P = 0.0220) of infant HBsAg positivity. The TDF group had less incidence of maternal alanine aminotransferase (ALT) levels above two times the upper limit of normal for ≥3 months (3.23% versus 14.29%, P = 0.0455), a lesser extent of postpartum elevations of ALT (P = 0.007), and a lower rate of ALT over five times the upper limit of normal (1.64% versus 14.29%, P = 0.0135) at 2 months postpartum. Maternal creatinine and creatinine kinase levels, rates of congenital anomaly, premature birth, and growth parameters in infants were comparable in both groups. At 12 months, one TDF-group child newly developed HBsAg positivity, presumably due to postnatal infection and inefficient humoral responses to vaccines.

CONCLUSIONS

Treatment with TDF for highly viremic mothers decreased infant HBV DNA at birth and infant HBsAg positivity at 6 months and ameliorated maternal ALT elevations. (Hepatology 2015;62:375-386.

Defective natural killer cell anti-viral capacity in paediatric HBV infection

Natural killer (NK) cells exhibit dysregulated effector function in adult chronic hepatitis B virus (HBV) infection (CHB), which may contribute to virus persistence. The role of NK cells in children infected perinatally with HBV is less studied. Access to a unique cohort enabled the cross-sectional evaluation of NK cell frequency, phenotype and function in HBV-infected children relative to uninfected children. We observed a selective defect in NK cell interferon (IFN)-γ production, with conserved cytolytic function, mirroring the functional dichotomy observed in adult infection. Reduced expression of NKp30 on NK cells suggests a role of impaired NK-dendritic cell (DC) cellular interactions as a potential mechanism leading to reduced IFN-γ production. The finding that NK cells are already defective in paediatric CHB, albeit less extensively than in adult CHB, has potential implications for the timing of anti-viral therapy aiming to restore immune control.