Autoimmune Hepatitis

Autoimmune Hepatitis

Autoimmune hepatitis is an unresolving inflammation of the liver of unknown cause.
It is characterized by the presence of

hepatitis (piecemeal necrosis or interface hepatitis),
hypergammaglobulinemia, and
autoantibodies in serum .

The definite diagnosis of autoimmune hepatitis
requires the presence of compatible laboratory and histologic findings (Table 1)

Findings that are compatible with autoimmune hepatitis but insufficient for a definite diagnosis of this condition justify the designation "probable autoimmune hepatitis" (Table 1). Patients who receive this designation typically have histories of alcohol consumption or exposure to hepatotoxic drugs or have serum levels of gamma globulin or autoantibody titers (or both) that are lower than those required for a definite diagnosis. Patients who are seronegative for antinuclear antibodies, smooth-muscle antibodies, and antibodies to liver/kidney microsome type 1 are also considered to have probable autoimmune hepatitis if they have other liver-associated autoantibodies of a less conventional nature, such as antibodies to asialoglycoprotein receptor, soluble liver antigen, liver-pancreas, or liver cytosol type 1. Patients with probable diagnoses must satisfy histologic criteria that are as rigid as those for patients with definite diagnoses (Table 1; Figure 1). In this context, predominant bile duct lesions and cholestatic features preclude the diagnosisss. Patients who are deficient in one or more of the criteria for a definite diagnosis must be assigned a probable diagnosis (Table 1).

Table 1. Criteria of the International Autoimmune Hepatitis Group for the DX of Autoimmune Hepatitis

Criterion    Probable DX Definite DX
Risk factors
Exposure to blood No Yes
Alcohol use
<25 g/d (for women) or <35 g/d (for men)          X
<40 g/d (for women) or <50 g/d (for men)   X
Use of hepatotoxic drugs No    X
Laboratory findings
Abnormal AST, ALT   X       X
Alkaline phosphatase < 3 X    X
Total globulin, gamma globulin, or IgG levels
>1.5 times the upper limit of normal          X
>1.0-1.5 times the upper limit of normal    X
Antibodies to nucleus (ANA), smooth
muscle, or liver/kidney microsome type 1
titer >1:80 (for adults) or >1:20 (for children)      X
Low titers or presence of other autoantibodies   X
Viral markers
Negative Hep. A, B,C, CMV, EB virus X   X
False + for antibodies to hepatitis C virus    X
Histologic findings
Interface hepatitis or piecemeal necrosis    X      X
Concurrent lobular hepatitis       X    X
No biliary lesions or other changes X X

Chronic Non-viral Hepatitis
Chronic hepatitis due to B, C, or D viruses must be differentiated from other forms of chronic hepatitis, such as: (1) corticosteroid-responsive chronic active hepatitis, (2) drug-induced hepatitis, (3) chronic alcoholic liver disease, (4) hemochromatosis, (5) Wilson's disease, (6) fatty infiltration, (7) neoplasms, and (8) a1-antitrypsin deficiency.

Corticosteroid-responsive Chronic Active Hepatitis (Autoimmune hepatitis)

Previously called autoimmune chronic active hepatitis, this rare form of chronic hepatitis, the cause of which is unknown, is often associated with autoimmune disorders and is responsive to corticosteroid therapy. The disorder is more common in women than in men, and about half of affected patients also have thyroiditis, rheumatoid arthritis, or collagen-vascular diseases. In addition to elevation of serum aminotransferases, laboratory findings may include hypergammaglobulinemia, autoantibodies to smooth muscle and liver membrane, and positive antinuclear antibody tests. However, autoantibody tests may all be negative. The disease has a range from piecemeal necrosis of the liver to liver failure. The pathologic changes are not pathognomonic, and the diagnosis is, therefore, based on the associated autoimmune phenomenon and the favorable response to corticosteroid therapy.

Prognosis varies and survival depends on the use of corticosteroids.