Characterization of hepatitis B virus in blood donors who were disqualified based on testing: genotype distribution, infectivity, and replicative fitness in human hepatocytes.

Abstract

Characterize hepatitis B virus (HBV) isolates from deferred blood donors identified by routine blood screening and confirmatory tests in the US, using virological, serological, and biochemical methods, and evaluate their infectivity in human hepatocytes. Forty-six (46) hepatitis B surface antigen (HBsAg) -positive plasma samples, including 32 reactive and 14 non-reactive for anti-HBV core (anti-HBc) were identified by blood donation testing and further analyzed for HBeAg/anti-HBe, liver disease markers (ALT and AST), and sequencing to determine virus genotype. To evaluate virus infectivity, plasma was used to inoculate humanized liver chimeric mouse-derived human hepatocytes (HLCM-HH). HBV DNA and HBsAg were monitored in culture media over time. Subjects with confirmed positive screening tests for HBV fell into two groups: 1) older, predominantly Caucasian or African American, anti-HBc non-reactive and genotype A, who had successfully donated blood on a previous occasion when they tested negative for HBV, suggesting recent horizontal transmission, 2) younger, predominantly Asian, anti-HBc reactive with genotypes B or C, attempting to donate for the first time, suggesting distant vertical transmission. HBV from all samples could infect and replicate in HLCM-HH cultures as measured by DNA. Infectivity could be blocked by incubating with anti-HBV immunoglobulin. Kinetics of DNA accumulation suggested more robust replication of viruses from anti-HBc non-reactive plasma. Analyses of plasma samples from HBV-infected individuals identified two groups differing in age, race, HBV genotype, and likely transmission route. HBV from anti-HBc non-reactive samples showed greater replicative fitness in HLCM-HH cultures compared to anti-HBc reactive samples.