An autoantibody is an antibody (a type of protein) produced by the immune system that acts against one or more of the individual's own proteins.
The causes of autoantibody production are varied and not well understood. It is thought that some autoantibody production is due to a genetic predisposition combined with an environmental trigger, such as a viral illness or a prolonged exposure to certain toxic chemicals. There is generally not a direct genetic link however. While families may be susceptible to autoimmune conditions, individual family members may have different autoimmune disorders, or may never develop an autoimmune condition. Researchers believe that there may also be a hormonal component as many of the autoimmune conditions are much more prevalent in women of childbearing age. While the initial event that leads to the production of autoantibodies is still unknown, there is a body of evidence that autoantibodies may have the capacity to maintain their production.
Source : Wikipedia
A large number of diseases and conditions (with unknown causes) are believed to be associated with immune system imbalances - examples include :Lupusplugin-autotooltip__plain plugin-autotooltip_bigLupus
"Systemic lupus erythematosus, also called SLE or lupus, is a disease of the immune system that causes the immune system to attack tissues in various parts of the body. The cause of lupus is unknown. Finding the cause is the object of major research efforts., Psoriatic Arthritis (PsA)plugin-autotooltip__plain plugin-autotooltip_bigPsoriatic Arthritis (PsA)
"Psoriatic arthritis, in short called PsA, is a rheumatologic disease that effects about 1,5 million Americans. About one in three people with the skin disease psoriasis, will get psoriatic arthritis. It affects the joints as well as the tendons, and it may also affect the spine., Schnitzler syndromeplugin-autotooltip__plain plugin-autotooltip_bigSchnitzler syndrome
Schnitlzler syndrome (SchS) is a rare auto-inflammatory disorder characterised by a chronic urticarial rash (hives), and signs and symptoms of systemic inflammation - including fever, bone pain, joint pain, muscle pain, headache, fatigue, and loss of weight. It was first described in 1972. , Fibromyalgiaplugin-autotooltip__plain plugin-autotooltip_bigFibromyalgia
"After osteoarthritis, fibromyalgia is the second most common 'rheumatic' disorder. Depending on the diagnostic criteria used, the prevalence is from 2% to 8% of the population." [...] Patients with fibromyalgia are likely to have a history of headaches, dysmenorrhea, temporomandibular joint disorder, chronic fatigue, irritable bowel syndrome and other functional gastrointestinal disorders,interstitial cystitis/painful bladder syndrome, endometriosis, and other regional pain syn… , Sjögren syndromeplugin-autotooltip__plain plugin-autotooltip_bigSjögren syndrome
Sjögren syndrome (SS) is a systemic long-term auto-immune condition which affects glands in the body's moisture-producing surfaces. Leading to dry eyes, dry mouth, dry skin, pain and fatigue. It can also strongly affect other organs, such as the lungs, kidneys, and nervous system., Neuromyotoniaplugin-autotooltip__plain plugin-autotooltip_bigNeuromyotonia
Neuromytonia (NMT) (also known as Isaac's syndrome, Isaac-Mertens syndrome, continuous muscle fiber activity syndrome, and quantal squander syndrome) is a condition affecting adults which causes spontaneous muscle contractions and cramps due to peripheral nerve hyperexcitability.