Miss Zhang is 22 years old, after successfully completing her undergraduate studies in college to find a well-paying, decent job. She should be actively facing the new environment in the workplace, but recently she was sullen, very depressed will. She told the truth only after being repeatedly asked by her friends. It turns out that some time ago, Zhang had a bad appetite at the same time appeared obvious weakness discomfort, so in the company of her parents to go to the hospital. What they didn’t expect was that their young daughter had been found to have abnormal liver function! What was even more disturbing was that after screening for various viral hepatitis markers, genetic, metabolic and drug-related liver damage, the doctors could not find a clear cause for her liver function abnormalities. So on the advice of the treating physician, Ms. Zhang was referred to a well-known tertiary hospital in the city for further consultation and treatment in the gastroenterology specialty. There, Zhang was clearly diagnosed with “autoimmune hepatitis”. After receiving hormone therapy, her condition was significantly controlled and she is now back to her former optimism and confidence. So, what kind of disease is autoimmune hepatitis? Ma Xiong, Department of Gastroenterology, Shanghai Renji Hospital Autoimmune hepatitis (AIH) occurs mainly in middle-aged and young women and often leads to severe hepatitis, which can progress rapidly to cirrhosis. Half of the patients have an insidious onset, and the most common symptoms are drowsiness or extreme fatigue and malaise. In addition, nausea, loss of appetite, weight loss, and abdominal discomfort or pain are more common. Physical examination findings include hepatomegaly, splenomegaly, and ascites. About 30% of patients already have cirrhosis at the time of diagnosis. More than 40% of patients have at least one other co-morbid autoimmune disease (most notably thyroid disease or rheumatoid arthritis). Approximately 10-20% of patients have no obvious symptoms and only have unexpectedly elevated serum transaminase activity on biochemical screening. More commonly, they are detected during screening for other conditions (most often concurrent endocrine or rheumatoid disease). In some patients, the first symptom may simply be arthritis or a skin rash, and the patient may initially be seen in rheumatology or dermatology. These “asymptomatic” patients tend to have milder disease and are better treated than those with chronic or acute onset. The typical serum biochemical abnormalities in AIH are primarily hepatitis-like, with elevated serum transaminase (AST, ALT) activity and bilirubin concentrations, and normal or slightly elevated serum alkaline phosphatase (ALP). g-glutamyl transpeptidase (GGT) may be elevated, but is not significant, and hyperglobulinemia due to elevated IgG is also a characteristic serologic change. One or more high titers of autoantibodies are present in almost all patients with AIH. Antibody titers often fluctuate over the course of the disease and may decline or turn negative in response to therapy, but they generally do not reliably reflect the severity of the disease. Approximately 70% to 80% of patients are serologically positive for antinuclear antibodies (ANA) and/or anti-smooth muscle antibodies (SMA). In addition, perinuclear staining anti-neutrophil plasma autoantibodies (pANCA) are present in 60% to 90% of patients with AIH. aNA, SMA and pANCA are not specific for AIH, but they are useful in the diagnosis. A small percentage of patients (approximately 3-4%) have antibodies to liver and kidney microsomes type I (anti-LKM1). HLA typing is not included in the routine screening for most liver diseases, but this information is useful in the diagnosis of AIH. Similar to other autoimmune diseases, AIH is closely associated with HLA A1-B8-DR3 haplogroups in European Caucasians, especially with DR3 and DR4. To help rule out other liver diseases, physicians sometimes recommend that patients undergo a liver aspiration biopsy to confirm the diagnosis of AIH. Since neither serum biochemical abnormalities nor autoantibody titers reliably reflect disease severity, liver biopsy can accurately evaluate the grading and staging of liver disease. The characteristic histologic change is interfacial hepatitis with infiltration of dense lymphocytes, mainly lymphoplasmacytes, in and around the confluent area or next to the interface and hepatocyte debris-like necrosis. In severe cases, lobular involvement, bridging-like necrosis of the confluent area-confluent area or central-confluent area, and hepatocellular rosette-like node formation are common. Patients with AIH with a clear histological basis (interface hepatitis, with or without fibrosis or cirrhosis) are subject to initial treatment with glucocorticoids, also in combination with azathioprine. The degree of elevation of transaminases and gamma globulin did not correlate with histologic severity and was not suggestive for initial treatment dose selection. In patients with only confluent inflammation, a combination of transaminase and/or gamma globulin levels and clinical symptoms is required to determine treatment. In asymptomatic patients or patients with only confluent inflammation and no fibrosis, treatment may be withheld, as the course of AIH tends to fluctuate, so the clinical picture, including liver biopsy findings, must be monitored closely. Initial treatment is often a combination of drugs to minimize the side effects of glucocorticoids. Another option is to induce remission with glucocorticoids followed by maintenance treatment with azathioprine. Combination therapy with glucocorticoids and azathioprine is effective in reducing mortality. Treatment may be long-term or even lifelong in most cases, so attention should be paid to the management of side effects. Although China is still a large country with viral hepatitis, with the rapid spread of medical knowledge in recent years, liver function abnormalities caused by hepatitis viruses are well known and there is some awareness of prevention, such as universal vaccination against hepatitis B, management of blood products and use of antiviral drugs. However, recurrent liver function abnormalities due to non-viral hepatitis are confusing to many patients and clinicians. After ruling out viral hepatitis and common causes such as drug, alcohol, and fatty liver disease, the possibility of AIH should be considered. At this point, the patient should be further tested for antibodies to autoimmune liver disease and, if necessary, a liver aspiration biopsy should be performed to clarify the diagnosis.