An autoimmune response occurs when the body's immune system mistakenly attacks its own healthy cells, tissues, or organs. Normally, the immune system protects the body from harmful invaders like bacteria and viruses. However, in autoimmune diseases, it fails to distinguish between foreign threats and the body’s own components, leading to inflammation and damage. Common examples of autoimmune diseases include rheumatoid arthritis, lupus, and multiple sclerosis. These conditions can affect various parts of the body, causing symptoms such as pain, fatigue, and organ dysfunction. Understanding autoimmune responses is crucial for developing effective treatments and managing these diseases.