Which immune condition occurs when the body attacks its own tissues?

The immune condition where the body attacks its own tissues is referred to as auto-immunity. In autoimmune diseases, the immune system mistakenly identifies healthy cells and tissues as foreign entities, leading to an inappropriate immune response that causes damage to the body's own organs or systems. This results in a range of possible symptoms and conditions, depending on which part of the body is affected. Common examples of autoimmune diseases include rheumatoid arthritis, lupus, and multiple sclerosis.

In contrast, immunodeficiency involves a weak or absent immune response, making the body more susceptible to infections. Allergies represent a hyperactive immune response to harmless substances, and infections occur when pathogens invade and multiply in the body, triggering an immune reaction. Each of these conditions has distinct mechanisms and consequences, but auto-immunity is specifically characterized by the immune system's attack on the body's own tissues.