PIgG was positive in up to 79% of patients with AIH that were negative for a conventional autoantibody and was positive in 90% of DI-ALH cases compared to 25% in DILI that were caused by the same drugs.<h4>Conclusions</h4>PIgG may complement current serologic tests to identify patients with liver injury in need of immunosuppressive treatment. The gene discussed is PIGG; the disease is autoimmune hepatitis.