LAUSR

Although overall infection rates of Hepatitis B virus (HBV) in the United States (US) remain stable, as many as 2.2 million persons are still chronically infected with Hepatitis B Virus (HBV)1. Persons who inject drugs (PWID) are at a higher risk of HBV infection and since 2009 three states (KY, TN, WV) have reported up to a 114% increase in cases of acute HBV infection due to higher infection rates among a non-Hispanic white populations (30–39 years), and injection drug users2. Hepatitis B vaccination is recommended as primary prevention for adults who are at increased risk for HBV infection, including PWID. However, data from the National Health Interview Survey indicate that hepatitis B vaccination coverage is low among adults in the general population3, and it is likely to be lower among injection drug users. Hepatitis B Surface Antigen (HBsAg) is the first serological marker to appear after HBV exposure and infection; this marker is included in the recommended panel for acute hepatitis diagnosis and accurate detection is necessary for early and accurate diagnosis. Serological testing challenges exist for HBsAg due to the high degree of genetic variability which can further be exacerbated by endogenous and exogenous pressures. The immuno-dominant region may have one or more mutations described as immune escape mutations which can decrease or abrogate HBsAg binding to antibodies used in immunoassays. Although the prevalence of these mutations is not well documented in the United States, international studies have shown that up to 79% of HBV-reactivated patients (vs 3.1% of control patients; p< 0.001) carry HBsAg mutations localized in immune-active HBsAg regions4. A study was conducted using a panel of 10 unique recombinant HBsAg immune escape mutants. Panel members were tested by commercially available HBsAg serological immunoassays. It was found that although commercially available HBsAg immunoassays are the primary diagnostic tool for HBV diagnosis, not all HBsAg immune escape mutants are detected, with some method detecting as few as 5 out of 10 of these mutant samples. Figure 1 Improvement is needed in commercially available methods for the accurate detection of HBsAg. Robert Gish, MD, Abbott (Consultant)AbbVie (Consultant, Advisor or Review Panel member, Speaker’s Bureau)Access Biologicals (Consultant)Antios (Consultant)Arrowhead (Consultant)Bayer (Consultant, Speaker’s Bureau)Bristol Myers (Consultant, Speaker’s Bureau)Dova (Consultant, Speaker’s Bureau)Dynavax (Consultant)Eiger (Consultant, Advisor or Review Panel member)Eisai (Consultant, Speaker’s Bureau)Enyo (Consultant)eStudySite (Consultant, Advisor or Review Panel member)Exelixis (Consultant)Fujifilm/Wako (Consultant)Genentech (Consultant)Genlantis (Consultant)Gilead (Consultant, Advisor or Review Panel member, Speaker’s Bureau)GLG (Consultant)HepaTX (Consultant, Advisor or Review Panel member)HepQuant (Consultant, Advisor or Review Panel member)Intercept (Consultant, Speaker’s Bureau)Ionis (Consultant)Janssen (Consultant)Laboratory for Advanced Medicine (Consultant)Lilly (Consultant)Merck (Consultant)Salix (Consultant, Speaker’s Bureau)Shionogi (Consultant, Speaker’s Bureau)Viking (Consultant)