Management of autoimmune and viral hepatitis in immunotherapy: a narrative review

Cancer immunotherapy has firmly established itself as a pillar of cancer care due to its advantages over traditional anti-tumor therapy but also carries limitations due to potential for severe adverse reactions. This review highlights the current understanding and management of patients with autoimmune and viral hepatitis immune in the setting of immune checkpoint inhibitor (ICI) therapy.A literature search was conducted on PubMed, Scopus, Google Scholar SEER*Stat databases (from inception to December 2022) using search terms: "immune checkpoint inhibitor", "autoimmune hepatitis", "viral hepatitis", "HBV pathogenesis", "HCV pathogenesis", "HBV reactivation", "HCV reactivation", "cancer immunotherapy", "immune related adverse events", "immune related hepatitis".Pre-existing autoimmune disease (AD), whether active or inactive, can predispose patients receiving ICI therapy to develop autoimmune disease flares or immune-related adverse events (irAEs). Thus, patients with AD have routinely been excluded from clinical trials and data on safety of ICI therapy are limited. Hepatic irAE can be seen in ICI therapy and is a distinct entity from autoimmune hepatitis (AIH). ICI therapy alters the immune environment in patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. Patients who had prior exposure to HBV are at risk for viral reactivation. However, the prevalence of viral hepatitis in patients receiving immunotherapy is under-recognized and can lead to increases in liver biochemical tests as well as deterioration of liver function ultimately limiting treatment.The high morbidity and mortality associated with immune-related hepatitis emphasizes the need for screening of underlying diseases, including autoimmune and viral hepatitis, prior to initiation of ICI. Presence of AIH or chronic viral hepatitis is the most important risk factor for hepatic adverse events in ICI therapy. Screening for AIH, HBV and HCV is paramount in patients who will undergo ICI therapy.