These recommendations, intended for use by physicians, suggest preferred approaches to the diagnostic, therapeutic and preventive aspects of care. They are intended to be flexible, in contrast to standards of care, which are inflexible policies to be followed in every case. Specific recommendations are based on relevant published information. To more fully characterize the quality of evidence supporting the recommendations, the Practice Guidelines Committee of the AASLD requires a class (reflecting benefit versus risk) and level (assessing strength

Erlotinib chemical structure or certainty) of evidence to be assigned and reported with each recommendation.4 The grading system applied to the recommendations has been adapted from the American College of Cardiology and the American Heart Association Practice

Guidelines, and it is given below (Table 1). AASLD, American Association for the Study of Liver Diseases; AIH, autoimmune hepatitis; ALT, alanine aminotransferase; ANA, antinuclear antibody; AST, aspartate aminotransferase; CYP1A2, cytochrome P450 1A2; HCV, hepatitis C virus; IBD, inflammatory bowel disease; IgG, immunoglobulin G; LKM-1, liver/kidney microsome type 1; PBC, primary biliary cirrhosis; PSC, primary sclerosing cholangitis; SMA, smooth muscle antibodies. Autoimmune hepatitis (AIH) is a generally unresolving U0126 inflammation of the liver of unknown cause. A working model for its pathogenesis postulates that environmental triggers, a failure of immune tolerance mechanisms, and a genetic predisposition collaborate to induce a T cell–mediated immune attack upon liver antigens, leading to a progressive necroinflammatory and fibrotic process in the liver.5,6 Onset is frequently insidious with nonspecific symptoms such as fatigue, jaundice, nausea, abdominal pain, and arthralgias at presentation,7 but the clinical spectrum is wide, ranging from an asymptomatic presentation8,9 to an acute severe disease.10,11 The diagnosis is based on histologic abnormalities, characteristic clinical and laboratory findings, abnormal levels of serum globulins,

and the presence Buspirone HCl of one or more characteristic autoantibodies.12-16 Women are affected more frequently than men (sex ratio, 3.6:1).17-19 and the disease is seen in all ethnic groups20-34 and at all ages.21,35-44 There are no robust epidemiological data on AIH in the United States. In Norway and Sweden, the mean incidence is 1 to 2 per 100,000 persons per year, and its point prevalence is 11 to 17 per 100,000 persons per year.45,46 A similar incidence and prevalence can be assumed for the Caucasian population of North America. Data on the natural progression of untreated disease are derived principally from experiences published prior to the widespread use of immunosuppressive agents for AIH and before the detection of the hepatitis C virus (HCV).