Hepatitis B Reactivation During Immunosuppressive Therapy or Cancer Chemotherapy, Management, and Prevention: A Comprehensive Review

CONTEXT Due to the close relationship between the immune system and the hepatitis B virus (HBV) replication, it is essential to monitor patients with current or past HBV infection under any type of immunosuppression. Cancer chemotherapy, immunosuppressive therapies in autoimmune diseases, and immunosuppression in solid organ and stem cell transplant recipients are the major reasons for hepatitis B virus reactivation (HBVr). In this review, the challenges associated with HBVr are discussed according to the latest studies and guidelines. We also discuss the role of treatments with different risks, including anti-CD20 agents, tumor necrosis factor-alpha (TNF-α) inhibitors, and other common immunosuppressive agents in various conditions. EVIDENCE ACQUISITION Through an electronic search of the PubMed, Google Scholar, and Scopus databases, we selected the studies associated with HBVr in different conditions. The most recent recommendations were collected in order to reach a consensus on how to manage patients at risk of HBVr. RESULTS It was found that the positive hepatitis B surface antigen (HBsAg), the high baseline HBV DNA level, the positive hepatitis B virus e antigen (HBeAg), and an absent or low hepatitis B surface antibody (HBsAb) titer prior to starting treatment are the most important viral risk factors. Furthermore, rituximab, anthracycline, and different types of TNF-α inhibitors were identified as the high-risk therapies. By analyzing the efficiency of prophylaxis on the prevention of HBVr, it was concluded that those with a high risk of antiviral resistance should not be used in long-term immunosuppressants. Receiving HBV antiviral agents at the commencement of immunosuppressant therapy or chemotherapy was demonstrated to be effective in decreasing the risk of HBVr. Prophylaxis could also be initiated before the start of therapy. For most immune suppressive regimes, antiviral therapy should be kept up for at least 6 months after the cessation of immunosuppressive drugs. However, the optimal time of prophylaxis keeping should be increased in cases associated with rituximab or hematopoietic stem cell transplants. According to the latest studies and guidelines from different bodies, recommendations regarding screening, monitoring, and management of HBVr are outlined. CONCLUSIONS Identification of patients at the risk of HBVr before immunosuppressive therapy is an undeniable part of treatment. Starting the antiviral therapy, based on the type of immunosuppressive drugs and the underlying disease, could lead to better management of disease.