In 2011, the Intractable
Liver Diseases Study Group of Japan, established novel diagnostic criteria for "
acute liver failure ", and published the classification criteria for the etiologies of
acute liver failure and late-onset
hepatic failure (LOHF) in 2013. According to this classification, HBV carriers showing acute
hepatitis exacerbation were divided into 3 subgroups; asymptomatic or inactive HBV carriers without drug exposure, asymptomatic or inactive HBV carriers developing HBV reactivation during and after immunosuppressive therapies and/or
antineoplastic chemotherapies and those with previously resolved HBV
infection showing iatrogenic HBV reactivation. In an annual nationwide survey in 2013, however, a patient with previously resolved HBV
infection was enrolled, in whom LOHF developed as a result of HBV reactivation despite in the absence of immunosuppressive therapies and/or
antineoplastic chemotherapies. Thus, the study group revised the classification criteria in 2015; HBV carriers developing acute
hepatitis exacerbation were classified into asymptomatic or inactive HBV carriers and patients with previously resolved HBV
infection, and both groups were further sub-classified into those receiving immunosuppressive therapies and/or
antineoplastic chemotherapies and those without such drugs exposure.