The 7 most common autoimmune diseases are Type 1 diabetes, rheumatoid arthritis, lupus, celiac disease, Graves' disease, multiple sclerosis, and psoriasis. Each of these diseases occurs when the body's immune system mistakenly attacks healthy cells, tissues, and organs. Type 1 diabetes is an autoimmune disorder in which the body's own immune system destroys the insulin-producing cells of the pancreas. Rheumatoid arthritis is an autoimmune disorder that affects the joints, causing inflammation and pain. Lupus is an autoimmune disorder in which the body's immune system attacks its own tissues, leading to inflammation and damage to the joints, skin, kidneys, blood cells, heart, and lungs. Celiac disease is an autoimmune disorder in which the body's immune system reacts to gluten, a protein found in wheat, rye, and barley. Graves’ disease is an autoimmune disorder that affects the thyroid gland, resulting in hyperthyroidism. Multiple sclerosis is an autoimmune disorder that affects the brain and spinal cord, causing muscle weakness, vision problems, and coordination issues. Finally, psoriasis is an autoimmune disorder that causes the overproduction of skin cells, leading to itchy, red patches on the skin.