drug-induced autoimmune liver disease:a diagnostic dilemma of an increasingly reported disease

The aetiology of autoimmune hepatitis(AIH) is uncer-tain but the disease can be triggered in susceptible patients by external factors such as viruses or drugs.AIH usually develops in individuals with a genetic back-ground mainly consisting of some risk alleles of the major histocompatibility complex(HLA).Many drugs have been linked to AIH phenotypes,which sometimes persist after drug discontinuation,suggesting that they awaken latent autoimmunity.At least three clini-cal scenarios have been proposed that refers to drug- induced autoimmune liver disease(DIAILD):AIH with drug-induced liver injury(DILI); drug induced-AIH(DI-AIH); and immune mediated DILI(IM-DILI).In addi-tion,there are instances showing mixed features of DI-AIH and IM-DILI,as well as DILI cases with positive autoantibodies.Histologically distinguishing DILI from AIH remains a challenge.Even more challenging is the differentiation of AIH from DI-AIH mainly relying in histological features; however,a detailed standard-ised histologic evaluation of large cohorts of AIH and DI-AIH patients would probably render more subtle features that could be of help in the differential diag-nosis between both entities.Growing information on the relationship of drugs and AIH is being available,being drugs like statins and biologic agents more fre-quently involved in cases of DIAILD.In addition,there is some evidence on the fact that patients diagnosed with DIAILD may have had a previous episode of hepa-totoxicity.Further collaborative studies in DIAILD will strengthen the knowledge and understanding of this intriguing and complex disorder which might represent different phenotypes across the spectrum of disease