Autoimmune diseases are mysterious conditions that are poorly understood by doctors. Basically, the immune system malfunctions and attacks healthy body tissues instead of pathogens. The role of the immune system is to defend the body against external threats, using a complex network of organs and cells. It is supposed to attack viruses, bacteria, parasites, fungi but also cancer cells or transplanted tissues. As the body's protection, the immune system normally reacts against these types of pathogens and foreign objects.
In order to deal with invaders, the immune system produces a special type of proteins named antibodies, which allow it to target them. For unknown reasons, the system can make an error that designates its own healthy tissues as invaders. It will then produce antibodies and send lymphocytes (or white blood cells) to attack them. This is known as an autoimmune reaction, which leads to inflammation, tissue damage and can have other serious health consequences.
Several possible causes of autoimmune reactions have been identified. The body sometimes considers a part of the body to be foreign if a virus, drug or other substance has changed its normal characteristics. It is also possible for compounds that are very similar to our own cells to enter the body, in which case both are targeted and attacked by the immune system. Some injuries can cause body fluids and other substances to spread in the blood, reaching unusual locations. This triggers a mistaken response of the immune system, which begins an attack on healthy cells in the area.
Some autoimmune reactions are actually started due to an error in the immune chain, if the system produces the wrong type of antibodies, which designate body tissues as targets.
Scientists divide autoimmune diseases in two types. The ones that only affect one body organ are considered organ-specific while all others that can attack several systems or organs are known as non-organ specific diseases.
The severity of autoimmune diseases is variable, some are not considered very threatening while others are extremely dangerous, depending on the organ that is affected. There are about 80 different autoimmune diseases in total. Even if the exact cause of these conditions remains a mystery, some scientists suspect a hormonal link. This is because women seem to be more likely to develop them during pregnancy. Autoimmune diseases can't be cured but it is possible to reduce the severity of their symptoms.
Autoimmune diseases can be treated indirectly, by simply reducing the activity of the immune system. This causes the attack to become less intense.
One of the common autoimmune diseases is scleroderma. In this case, the immune system attacks the skin, causing scars to form. The skin can become thick, joints lose their flexibility and the skin is covered by ulcers.
Rheumatoid arthritis happens when the immune system attacks the joints. The joints are first marked by antibodies and then attacked by white cells. The symptoms are severe inflammation, pain and swollen joints. Severe and permanent joint damage results if the disease is not treated. The only solution is to decrease the overall activity of the immune system, using one of the available oral or injectable medications.
Lupus, also named systemic lupus erythematosus, is another common autoimmune disease. It can affect many parts of the body, with the blood cells, lungs, joints, kidneys and nerves being the usual targets of the immune attack. Daily oral doses of prednisone are usually required, a steroid that lowers the overall immune response.
Inflammatory bowel disease, commonly abbreviated as IBD, targets the tissues that line the intestines. The symptoms are fever, abdominal pain, diarrhea, rectal bleeding, weight loss and irregular defecation. Inflammatory bowel disease has several varieties, the most common are Crohn's disease and ulcerative colitis. It is also treated by suppressing the immune system.
Multiple sclerosis or MS is a severe condition in which the nerve cells come under attack. This causes numerous symptoms such as lack of coordination, blindness, weakness, muscle spasms, pain and even death. Several immune suppressing drugs can be used to control this disease.
An autoimmune disease can also cause a variant of diabetes named type 1 diabetes mellitus. In this case, the cells in the pancreas that normally produce insulin are destroyed by the mistaken immune attack. This disease is lethal without daily insulin shots.
The Guillain-Barre syndrome causes weakness, sometimes with extreme symptoms. It is caused by an immune system that targets the nerves that control muscles, usually in the legs but sometimes in the arms or other areas. A therapy named plasmapheresis is used to control it, which involves filtering the blood.
Psoriasis is a type of autoimmune reaction that affects the skin. The system sends T-cells, which are a very active type of immune cell, to the skin. These cause rapid division of the cells in the area, which forms scaly plaques on the surface.
Graves' disease is a form of hyperthyroidism. Antibodies sent by the immune system to the thyroid gland make it produce large amounts of hormones that are released in the blood stream. This can have serious consequences, from brittle hair, nervousness or irritability to loss of weight and irregular heart rate. The disease is usually controlled by completely disabling the thyroid gland through surgical removal or chemical destruction.
Hashimoto's thyroiditis is a different type of thyroid gland problem. It can be considered the opposite of Graves' disease, since the gland is attacked by the immune system, which leads to hypothyroidism, which is a low production of the thyroid hormones. The symptoms develop slowly and consist of weight gain, fatigue, constipation, depression, intolerance to cold or dry skin. These issues can be reversed by taking pills with artificial hormones.
Myasthenia gravis is another condition that leads to muscular weakness. Immune system antibodies target the nerves and they can no longer control muscles properly. The weakness become worse in time. The disease can be treated with mestinon, a drug based on pyridostigmine.
Vasculitis is an umbrella term for a series of autoimmune diseases that harm blood vessels. The symptoms can be very different, since any tissue or organ can be affected, with unpredictable effects. A corticosteroid such as prednisone is normally used to reduce the overall activity of the immune system.
Nobody knows what exactly causes autoimmune diseases but several risk factors have been identified. Probably the main one is genetic inheritance, since they tend to affect people from the same family. However, the inherited disease is not the same and relatives can have different autoimmune diseases. It seems that only a general vulnerability is determined by genetics and there are other reasons that actually trigger the defective immune response. Because of this behaviour, some scientists think that environmental factors are actually more important. The logic is that people from one family are all exposed to the same environmental conditions, which might explain their common vulnerability to autoimmune diseases in general. Some infections have also been observed to either start such diseases or make them more virulent.
Gender is another important factor, since a higher proportion of women (around 75% of total) develop autoimmune diseases. The cause could also be hormonal, since women are usually affected during pregnancy, when hormone levels increase. Important hormonal changes like menopause, pregnancy and childbirth have a direct effect on autoimmune diseases and can increase or decrease the intensity of the attack.