Autoimmune pathology

2021-01-26 12:00 AM

There is no mechanism yet to explain all cases of autoimmune diseases, it is possible that the mechanism may vary with the disease.

Outline

Autoimmune disease is a medical condition that occurs because the immune system loses the ability to distinguish between external antigens and autoantigens. Self-antigens are a part of the body that, for some reason, becomes a foreign body. The body's own antibodies against these autoantigens cause autoimmune disease to occur.

The autoimmune disease should be differentiated from an autoimmune reaction, an autoimmune reaction that produces autoantibodies but does not cause disease, such as autoantibodies produced after tissue necrosis contributing to the elimination of degradable substances.

The disease also has many different names such as autoantibody disease, autoimmune disease, self-sustaining disease, auto-allergic disease, auto-hypersensitivity disease, the most commonly used name is an autoimmune disease.

Mechanism of pathogenesis

There is no mechanism yet to explain all cases of autoimmune diseases, it is possible that the mechanism may vary with the disease.

Normally, when the fetus has contact with the endothelial system, the re-exposure will be recognized as belonging to the body, which does not give rise to antibodies, that is tolerability. immunity. This immune tolerance and gives rise to autoimmune disease in the following 4 cases:

Case 1

There is a coincidence between a foreign antigen and a body component. The body produces antibodies against this antigen (eg bacteria) while also fighting against the part of the antigen-like structure. For example, rheumatism, hexosamine is present in streptococci (group A haemolysis is also present in heart valve glycoprotein, therefore antibodies are anti-streptococci, resistant to heart valves.

Case 2

Due to the effects of intoxication, infection, and trauma, some cells of the body are damaged and changed into foreign bodies, immune cells consider them as foreign antigens and produce antibodies. again. For example, viral hepatitis.

Case 3

Some parts of the blood body do not come into direct contact, immune cells cannot reach, when they appear in the blood (e.g., trauma) the body produces antibodies against, as in eye patients, when damaged one side causes antibodies to appear against the other eye causing sympathetic eye inflammation (ophthalmic sympathies).

Case 4

Due to damage or impairment of the ability to control the immune cells themselves. The autoantibody synthesis inhibition system is impaired, so the immune cells develop and produce antibodies against the familiar components of the body. Some diseases of the endothelial retinal system, for example, are often accompanied by haemolytic anaemia due to the appearance of autogenous erythrocyte antibodies.

Types of antibodies and the consequences of reactions

Types of autoantibodies

Autoantibodies in autoimmune diseases cause disease in many ways, such as destroying, damaging, and sometimes by stimulating the target organ, causing different manifestations. There are two types of autoantibodies

Main autoantibodies: cause real diseases such as anti-red blood cell surface antibodies, anti-leukaemia, anti-basal membrane, anti-acetylcholine receptors.

Secondary autoantibodies: accompanied by autoimmune disease, not the cause of the disease. For example, anti-gastric antigen in Hashimoto's disease is an autoantibody that is nonspecific for the diseased organ, which is thyroid, anti-nuclear, anti-mitochondrial, anti-myocardial.

Consequences of autoimmune reactions

Cytostasis due to phagocytosis, complement, cytotoxic T lymphocytes (haemolytic anaemia).

Deposition of immune complexes in target tissues (systemic lupus erythematosus).

Chronic inflammation with mononuclear infiltrates (Hashimoto).

Cell necrosis, fibrotic degeneration (acute glomerulonephritis).

Basedow.

General characteristic autoimmune disease

With the concept of autoimmune disease as mentioned above, so there is abuse in diagnosis. Besides, there are still many conflicting opinions about whether many diseases are really autoimmune diseases or not? In general, understanding of the disease still has to be continued to unify. Here are some features of autoimmune diseases:

The disease is common in young or elderly people (usually from 20 to 40 years old). Children and the elderly are less common. Women meet more than men. Often there are genetic factors, of a family nature.

The disease progresses in waves, gradually (so the disease is called self-sustaining disease) usually complicated progression, ranging from acute, acute to mild, persistent.

Can damage multiple organs at the same time.

There is no obvious direct cause. However, the disease can occur after the following situations: poisoning, acute, chronic infection, pregnancy, mental or physical trauma, physical agents such as sunburn, K, after taking certain drugs, an illness may respond quite well to some immunosuppressants, especially corticosteroids.

In terms of diagnosis, there is no common standard for autoimmune diseases, however clinical, progression and some tests suggest autoimmune diseases such as unreasonable reduction of red blood cells, white blood cells, and platelets. may include lymphocytosis, increased blood sedimentation rate, gamma - globulin ...

Accurate diagnosis is based on the detection of autoantibodies, the more specific, the more accurate this can be done only in specialized centres.

Classification of autoimmune diseases

Autoimmune diseases are groups of heterogeneous diseases, the mechanism of pathogenesis is not fully understood, and the classification is still controversial. The following is the widely agreed rating:

Certain autoimmune diseases

Self-antigens and autoantibodies have been found. Diseases can be tested, for example, systemic lupus erythematosus, Goodpasture syndrome, myasthenia gravis, Hashimoto's thyroiditis.

The most likely diseases

Self-antibodies, eg malignant anaemia with autoantibodies against foreign factors and against parietal cells of the gastric mucosa have been detected.

Possible diseases

Due to clinical manifestations and post-treatment improvement with immunosuppressants, eg haemorrhagic ulcerative colitis.

React

Including many diseases, autoantibodies have been found but it is not clear whether these autoantibodies act as pathogenic or merely as a marker of disease. For example, anti-myeline antibodies in sclerosis.

Some autoimmune diseases

Colloid diseases

Systemic lupus erythematosus Due to autoantibodies to antigens, such as DNA, Ro, Sm.

Usually occurs in women, young (90%). Damage to many organs. Skin: butterfly-shaped rash on the face, ulceration of the oral mucosa, alopecia. Musculoskeletal: inflammation, myalgia, polyarthritis. Kidney: nephrotic syndrome. Nerve: damage to many places of nerves. Cardiovascular: inflammation of the pericardium, dry, fluid, spasm, myocarditis, endocarditis, myocardial infarction due to coronary artery inflammation, capillary thrombosis. Lungs: pneumonia with atelectasis, pulmonary fibrosis, pleurisy. Haematology: blood clotting disorders, anaemia, haemolysis. Gastrointestinal: diarrhoea, intestinal perforation, intestinal obstruction, acute pancreatitis, increased liver enzymes. Eyes: retinal vasculitis causing blindness, conjunctivitis, optic neuritis, dry eyes.

Rheumatoid Arthritis Due to autoantibodies to HLA DR4, DR1, the cause of the onset may be the Epstein Barr virus.

Sjogren syndrome Due to self-antibodies against salivary duct epithelial cells, autoantibodies to antigens, causes dry syndrome (eyes, saliva, nose).

Endocrine disease

Hashimoto's chronic thyroiditis Diseases caused by antibodies to Thyroglobulin, anti-Thyroperoxidase, microscopic particles. Usually occurs in women, the thyroid gland can be large or not, lymphatic infiltrates. The first stage may have transient hyperthyroidism followed by hypothyroidism, which progresses slowly, possibly with other autoimmune diseases.

Basedow disease due to autoantibodies TSI, TBII, TGI.

Diabetes mellitus (type 1) due to anti-Langerhans antibodies, anti-glutamic acid decarboxylase, anti-beta cells.

Some other autoimmune endocrine diseases:

Primary Addison: Children with disabilities against the adrenal cortex.

Primary hypoparathyroidism: Children with disabilities fight the main cells of the parathyroid gland.

Autoimmune primary infertility: Children with disabilities fight sperm.

Haematology

Biermer malignant anaemia caused by children with anti-parietal anti-walled children, children with disabilities against FIs and children with disabilities against FI + Vitamin B12 cause iron deficiency anaemia, atrophy of the mucous membranes of the tongue, stomach with lymphocytosis.

Autoimmune haemolytic anaemia caused by CWD against natural red blood cell surface antigen, acute or chronic haemolytic system, occurs at any age. Acute, usually occurs in children after some acute diseases such as pneumonia caused by Mycoplasma, Eaton, mumps, shingles, chickenpox, influenza, viral hepatitis ... Chronic, usually in adults after chronic diseases such as chronic lymphocytes, systemic lupus erythematosus, Hodgkin, myasthenia gravis, bleeding colorectal inflammation, Basedow, cirrhosis ...

Autoimmune thrombocytopenia Due to anti-thrombocytopenic children with disabilities, less common disease, causing single chronic thrombocytopenic purpura or a combination of some chronic diseases such as chronic lymphoma, Hodgkin, non-Hodgkin lymphoma, thymus TM haemolytic anaemia, systemic lymphoma ...

Myelogenous aplasia is caused by autoantibodies against bone marrow stem cells.

Leukopenia due to anti-leukocyte autoantibodies.

Nerve

Severe myasthenia gravis.

Scattered sclerosis due to anti-myeline autoantibodies usually occurs in young people (15-40 years old) with various nerve damage, motor-sensory disturbances, cerebellum, eye damage, marrow damage. bone, with mental abnormalities. The disease progresses gradually worsening waves.

Guillain Barré syndrome polyneuropathy, unexplained about children with disabilities, causes peripheral paralysis of the lower extremities, cerebrospinal fluid: cell protein dissociation.

Digestive liver bile

Primary biliary cirrhosis due to autoantibodies to Mitochondria.

Chronic hepatitis attacks due to the anti-smooth muscle autoantibodies, the anti-lipoprotein antibodies of liver cells.

Coeliakie's disease is caused by autoantibodies to reticuline.

Haemorrhagic ulcer: no autoantibodies have been found.

Crohn's disease causes narrowing of each segment of the digestive tract, especially the colon, clinical and subclinical easily mixed with colonic tuberculosis, has not found autoantibodies.

Kidney

Some glomerulonephritis and tubular inflammation: due to autoantibodies to antigen and tumour antigens, anti-IgG.

Goodpasture syndrome: due to anti-glomerular basal membrane autoantibodies.

Lung

Goodpasture syndrome: due to anti-alveolar basal membrane autoantibodies. Idiopathic fibrosis alveoli. Wegener's granulomatous disease, the latter two diseases with unknown autoantibodies.

Gives

True Pemphigus: Self-antibody against the epidermal intercellular substance. Pemphigus botü: autoantibodies against the basal membrane of the epidermis. Vitiligo self-antibodies against melanocyte.

Vasculitis

Such as temporal artery diseases, Wegener's granulomatosis, Churg Strauss disease, peri-artery node inflammation. These diseases have unknown autoantibodies.

Conclude

Autoimmune disease is a complex set of diseases with unknown causes and pathogenesis mechanisms, so there are still many things that are not expected to be treated, in the future, specific monoclonal antibodies will be treated. There is a lot of promise.