The topic of Hepatitis B virus (HBV) reactivation has been discussed on this blog before (see link below).  Another excellent review on this topic (R Lomba, TJ Liang. Gastroenterol 2017; 152: 1297-1309) has been published.  The authors examine the course and mechanisms of HBV reactivation.  They divide the risk of reactivation into three groups: high, moderate and low risk and proposed management.

High risk groups, which have >10% risk of reactivation) include the following

• B-cell-depleting agents including rituximab, ofatumumab, alemtuumab, and ibritumumab
• High-dose corticosteroids (>20 mg/day in adults)
• Antracyclines including doxorubicin
• Potent TNF-α inhibitors: infliximab, adalimummab, certolizumab, and golimumab
• Local therapy ofr HCC including TACE (transarterial chemoembolization)

Moderate groups (1-10% reactivation) include cytokine-based Rx (eg. abatacept, ustekinumab, natalizumab, vedolizumab), cyclosporine, systemic chemotherapy, moderate corticosteroid dosing

Low risk groups (<1% reactivation) include thiopurines (azathioprine, 6-mercaptopurine), and methotrexate as well as short-term low-dose corticosteroids.

Management:

• For HBV screening, the authors recommend HBsAg and anti-HBc testing
• Prophylactic therapy with potent oral anti-HBV therapies are recommended for those at moderate or high risk of reactivation.  In those at low risk, the options include prophylactic treatment or watchful monitoring.
• A more detailed algorithm is provided in Figure 3.  In those with HBsAg positivity, if HBV DNA is less than 2000 U/mL, this algorithm suggests monitoring labs (HBsAg, ALT, HBV DNA every 3 months)

Mechanisms of HBV reactivation are discussed.  For example, with TNF-α inhibitors “can activate a unique host antiviral pathway, the APOBEC (apolipoprotein B mRNA editing enzyme, catlytic polypeptide-like) proteins, that cause the degradation of cccDNA in HBV-infected cells. Thus, blocking this endogenous antiviral pathway may lead to a higher HBV replication state and HBV reactivation.”

My take: In pediatric gastroenterology, we do not see a lot of HBV reactivation. Nevertheless, we do use many of the medications which can trigger HBV reactivation and need to keep these recommendations in mind.

Related blog post: What HBV Testing is Needed Before TNF Inhibitor Therapy

Suntrust Park