Dr Maxwell Adeyemi

AUTOIMMUNE diseases result when your immune system is overactive, causing it to attack and damage your body's own tissues.

Normally, your immune system creates proteins called antibodies that work to protect you against harmful substances such as viruses, cancer cells and toxins. But with autoimmune disorders, your immune system cannot tell the difference between invaders and healthy cells.

There are more than 100 different autoimmune diseases, which together affect people across the globe. It's not clear exactly what causes or triggers them.

Types of autoimmune diseases

Rheumatoid arthritis. The immune system produces antibodies that attach to the linings of your joints. Immune-system cells then attack the joints, causing inflammation, swelling and pain. If left untreated, RA gradually causes permanent joint damage.

Systemic lupus erythematosus. When you have lupus, you develop autoimmune antibodies that can attach to tissues throughout your body. This disease most often attacks your joints, lungs, blood cells, nerves and kidneys.

Inflammatory bowel disease. The immune system attacks the lining of your intestines, causing bouts of diarrhoea, rectal bleeding, urgent bowel movements, abdominal pain, fever and weight loss. Ulcerative colitis and Crohn's disease are the two main forms of this condition.

Multiple sclerosis. Your immune system attacks nerve cells, causing symptoms that may include pain, blindness, weakness, poor co-ordination and muscle spasms.

Type 1 diabetes. In this condition, the antibodies attack and destroy insulin-producing cells in your pancreas. People with type 1 diabetes need insulin shots to survive.

Guillain-Barre syndrome. Here your immune system attacks the nerves controlling the muscles in your legs and sometimes those in your arms and upper body. This leads to weakness, which can sometimes be serious.

Chronic inflammatory demyelinating polyneuropathy. Similar to Guillain-Barre, this disease also involves the immune system attacking the nerves. But the symptoms last much longer. If it's not treated early, about 30 per cent of people with this condition will eventually need to use a wheelchair.

Psoriasis. When you have psoriasis, immune system blood cells called T-cells collect in your skin. Your immune system stimulates skin cells to reproduce quickly, producing silvery, scaly plaques on your skin.

Graves' disease. In this disease, your immune system produces antibodies that cause your thyroid gland to release too much thyroid hormone into your blood (hyperthyroidism). Symptoms can include bulging eyes, weight loss, nervousness, irritability, rapid heart rate, weakness and brittle hair.

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

Myasthenia gravis.