In response to an unknown trigger - or no trigger!-, the immune system may inappropriately begin producing antibodies that instead of fighting infections, attack the body's own tissues, associated with abnormally low activity or over activity of the immune system. Immune deficiency diseases decrease the body's ability to fight invaders, causing vulnerability to infections.

Children growing up in rural areas, around animals, and in larger families seem to develop asthma less often than do other children. This might be due to increased exposure to particular viruses, bacteria or parasites that helps the immune system to develop and orient.
# Early germ exposure and asthma, Mayo Clinic
# The Hygiene hypothesis, PMCID: PMC4918254
# Environmental Antigens and the Rise of Allergy, PMCID: PMC5418306
# Unpublished own research “ecosymbiotism” where using Bronchovaxom®; an extract of eight different kinds of bacteria involved in respiratory infections intended for recurrent respiratory tract infection, used for pediatric cases of chronic allergic asthma over 3-9 months with prohibition of antiseptic soaps, reduced asthma recurrence by 62-88%.

These conditions may be restricted to specific organs eg, autoimmune thyroiditis, psoriasis, type I diabetes mellitus, inflammatory bowel diseases,,etc, or a particular tissue in different parts of the body eg, multiple sclerosis, systemic lupus erythematosus,,etc.
There are more than 80 different types of autoimmune diseases; their onset is typically slow, sometimes occurring over the course of years, and the symptoms are often nonspecific (eg, fatigue, general malaise, fever).

The World Incidence and Prevalence of Autoimmune Diseases is Increasing

In a 30 identified studies. The means ± s.d. of the net % increased /year incidence and prevalence of autoimmune diseases worldwide were 19.1±43.1 and 12.5±7.9, respectively.

• Rheumatoid arthritis. Immune system cells attack the joints lining, causing inflammation, swelling, and pain. If untreated, rheumatoid arthritis causes gradually causes permanent joint damage.

• Systemic lupus erythematosus (lupus). Autoimmune antibodies that can attach to tissues throughout the body. The joints, lungs, blood cells, nerves, and kidneys are commonly affected in lupus.

• Inflammatory bowel disease (IBD). The immune system attacks the lining of the intestines, causing episodes of diarrhea, rectal bleeding, urgent bowel movements, abdominal pain, fever, and weight loss. Ulcerative colitis and Crohn's disease are the two major forms of IBD.

• Multiple sclerosis (MS). The immune system attacks nerve cells, causing symptoms that can include pain, blindness, weakness, poor coordination, and muscle spasms.

• Type 1 diabetes mellitus. Immune system antibodies attack and destroy insulin-producing cells in the pancreas. By young adulthood, people with type 1 diabetes require insulin injections to survive.

• Guillain-Barre syndrome. The immune system attacks the nerves controlling muscles in the legs and sometimes the arms and upper body. Weakness results, which can sometimes be severe.

• Chronic inflammatory demyelinating polyneuropathy. Similar to Guillian-Barre, the immune system also attacks the nerves in CIDP, but symptoms last much longer. About 30% of patients can become confined to a wheelchair if not diagnosed and treated early.

• Psoriasis. In psoriasis, overactive immune system blood cells called T-cells collect in the skin. The immune system activity stimulates skin cells to reproduce rapidly, producing silvery, scaly plaques on the skin.

• Graves' disease. The immune system produces antibodies that stimulate the thyroid gland to release excess amounts of thyroid hormone into the blood (hyperthyroidism). Symptoms of Graves' disease can include bulging eyes as well as weight loss, nervousness, irritability, rapid heart rate, weakness, and brittle hair.

• Hashimoto's thyroiditis. Antibodies produced by the immune system attack the thyroid gland, slowly destroying the cells that produce thyroid hormone. Low levels of thyroid hormone develop (hypothyroidism), usually over months to years. Symptoms include fatigue, constipation, weight gain, depression, dry skin, and sensitivity to cold.

• Myasthenia gravis. Antibodies bind to nerves and make them unable to stimulate muscles properly. Weakness that gets worse with activity is the main symptom of myasthenia gravis.

• Vasculitis. The immune system attacks and damages blood vessels in this group of autoimmune diseases. Vasculitis can affect any organ, so symptoms vary widely and can occur almost anywhere in the body.