Autoimmune liver disease

Introduction to autoimmune liver disease Autoimmune liver disease is a type of autoimmune disease in which the liver is a relatively specific immunopathologically injured organ, including autoimmune hepatitis (AIH), primary biliary cirrhosis (PBS), and primary sclerosing. Cholangitis (PSC) and the overlap syndrome between any two of these three diseases often coincide with extrahepatic immune diseases. Its diagnosis is mainly based on specific biochemical abnormalities, autoantibodies and dry tissue characteristics. With the improvement of the level of cognition and diagnosis, the prevalence of autoimmune liver diseases reported at home and abroad has increased year by year, and it has received more and more attention and attention. Mainly manifested as the destruction of autoimmune tolerance, a characteristic cytological change in the immune response in the liver tissue, namely T cell infiltration. The target antigen of T cells is considered to be cytochrome P450IID6, mitochondrial pyruvate hydrodease (MCPD) and asialoglycoprotein receptor protein (ASGP-R protein), all of which are hepatocyte-specific antigens. . basic knowledge The proportion of illness: 0.03% Susceptible people: no specific population Mode of infection: non-infectious Complications: liver cancer

Causes of autoimmune liver disease

Potential stimuli

Pathogenesis of autoimmune liver disease Autoimmune liver disease (AIH) must be activated by antigen. The pathogenesis of AIH induced by environmental factors has not been elucidated, and viruses (such as HBV, HCV, Epstein-Barr virus, measles virus, etc.) are relatively positive in stimulating immune responses. Viral epitopes cause cross-reactivity through "molecular mimicry" and certain liver antigens with the same determinants, leading to autoimmune liver disease. A variety of non-specific autoantibodies can be detected in the serum of some patients infected with HCV. It is speculated that HCV infection stimulates the expression of HIA on the surface of the liver cell membrane and changes the protein component on the membrane of the liver cell. Biological, physical or chemical factors can also trigger changes in autoantigens. Drugs such as methyldopa, nitrofurantoin, diclofenac, minocycline, and interferon cause liver damage similar to AIH.

Genetic susceptibility

The exploration of genetic susceptibility has focused on the superfamily of immunoglobulins, including genes located in MHC-encoding HLA, and genes encoding immunoglobulin and T cell receptor (TCR) molecules.

The antigen is presented to the cell surface by antigen-presenting cells to bind to HLA-II molecules, and the process of recognizing and activating T cells by T cell receptor (TCR) is affected by MHC allele polymorphism encoding HLA molecules. The amino acid sequence of amino acids 67 to 72 of the DR polypeptide chain located in the HLA class II molecular antigen binding groove, especially the position of amino acid 71 is importantly related to the occurrence of AIH, because the amino acid at position 71 is located at the top of the antigen binding groove. The position determines the ability of HLA to bind to the antigen and thereby be recognized by the TcR. The MHC allele encoding this amino acid sequence differs among different populations. The amino acid sequence of 67-72 in Northern Europe and North America with AIH genetic susceptibility tends to be Leu-Leu-Glu-G1n-Lys-Arg, of which The amino acid at position 71 is lysine (Lys), and the MHC alleles encoding this sequence are DRB0.1030, DRB3.0101 and DRB1.001. The 71st amino acid of the DR4-positive Japanese having a genetic predisposition to AIH is arginine (Arg), and its coding gene is DRB1.040. Other different geographical groups also have their own HLA genetic susceptibility characteristics.

In addition to HLA, genetic differences in TCR, vitamin D receptor (VDR), T011-like receptor-4 (TLR-4), TGF, CD45, etc. may also affect the susceptibility of AIH. It is also related to the polypeptide nature of the TNF- gene.

Changes in autoimmune response

Mainly manifested as the destruction of autoimmune tolerance, a characteristic cytological change in the immune response in the liver tissue, namely T cell infiltration. The target antigen of T cells is considered to be cytochrome P450IID6, mitochondrial pyruvate dehydrogenase (MCPD) and asialoglycoprotein receptor proteins (ASGP-R protein), all of which are liver Cell-specific antigen.

Due to the destruction of immune tolerance, activated CD4+ T cells (including Th1 and Th2) stimulate the B cells to produce antibodies against autoantigens by direct contact with TB cell membranes and release of cytokines to initiate an immune injury response. In addition, cytokines also kill liver cells by activating CD8+ T cells mediated ADCC effect, activate TNF or Fas system to mediate hepatocyte apoptosis, and activate stellate cells to promote liver fibrosis.

Hepatocyte injury mechanism mediated by AIH immunity

The normal component of the hepatocyte membrane is recognized by the helper T cells (Th and Th2) as "isoantigen antigen" with the help of antigen presenting cells (APc) or hepatocytes themselves, and this recognition is carried out with the participation of HLA class II molecules. If the inhibitory T cells (Ts) do not intervene, it is bound to initiate a variety of immune effect mechanisms to damage the liver parenchyma cells.

Children and young AIH patients have low levels of inhibitory T cells and are also dysfunctional. Defects in immunoregulatory mechanisms render control of immune reactivity to helper T cells out of control. This damage is also manifested as liver specificity and is associated with the dominant expression of the HLA molecular product B8/DR3. Hepatocytes express HLA class II molecules and immune regulation disorders, which form the basis of autoimmunity against hepatocytes.

Autoimmune liver disease prevention

Can improve hepatitis B to improve immunity Chinese medicine

1 can enhance the function of macrophages. Hedyotis diffusa, Ligustrum lucidum, honeysuckle, spatholobus, and soy root.

2 can enhance the function of B cells and improve the immune ball. Dodder, Huang Jing, Cynomorium, Curculigo, etc.

3 can enhance the function of T cells. Astragalus, ginseng, Codonopsis, Atractylodes, Ganoderma lucidum, mulberry parasitic and so on.

4 can clear the immune complex. Raw land, rhubarb, peach kernel, safflower, motherwort, salvia, red peony.

5 can activating blood circulation and strengthening immune function. Salvia, spatholobus, peach kernel, safflower, turmeric, puerarin, etc.

Autoimmune liver disease complications Complications

Liver cancer, hepatic diabetes.

Symptoms of autoimmune liver disease Common symptoms Joint swelling and pain, fatigue, fever, rash, low fever, jaundice, erythrocyte sedimentation rate

Clinically, there are various manifestations of autoimmunity, such as jaundice, fever, rash, arthritis and other symptoms, and high gamma globulinemia can be seen, erythrocyte sedimentation rate is accelerated, and autoantibodies in blood are positive. About 20% to 25% of patients have an onset of acute viral hepatitis, which is characterized by jaundice, anorexia, and bloating.

Susceptible population

Clinical manifestations are more common in women, mainly in adolescence. In addition, menopausal women are also more common. The onset is mostly insidious or slow, and may have joint pain, low fever, fatigue, rash, amenorrhea and the like.

The characteristics of this disease:

There are extrahepatic manifestations, and sometimes other symptoms can mask the original liver disease.

The extrahepatic manifestations of this disease are:

(1) symmetry, migratory arthritis, recurrent attacks, no joint deformities;

(2) hypothermia, rash, cutaneous vasculitis and subcutaneous hemorrhage;

(3) endocrine disorders, acne, hairy, female amenorrhea, male breast development, hyperthyroidism, diabetes, etc.;

(4) renal tubular acidosis, glomerulonephritis;

(5) pleurisy, interstitial pneumonia, atelectasis, fibrous alveolitis;

(6) Ulcerative colitis, Sjogren's syndrome.

Autoimmune liver disease examination

Autoimmune liver disease, a disease with unknown pathogenesis, is associated with many diseases, and clinical diagnosis is difficult because the initial clinical symptoms are similar to those of viral hepatitis. Therefore, accurate and timely detection of specific autoantibodies against autoimmune liver disease is undoubtedly of great significance for diagnosis and further treatment.

Diagnosis and differentiation of autoimmune liver disease

Test the antigen of the virus, test the human body's antibodies, and test the virus's DNA.

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