What is the term for a disease that occurs when the immune system attacks the body's own cells?

The term for a disease in which the immune system mistakenly attacks the body's own cells is known as an autoimmune disease. In autoimmune disorders, the body's defense mechanisms, which are designed to protect against foreign invaders such as viruses and bacteria, become misdirected and target healthy cells and tissues. This can result in inflammation and damage to various organs and systems, leading to a range of symptoms depending on which parts of the body are affected.

Autoimmune diseases can include conditions such as rheumatoid arthritis, lupus, and multiple sclerosis, among others. The underlying cause of these diseases can often be complex and may involve genetic, environmental, and immunological factors.

In contrast, an allergy refers to an overreaction of the immune system to harmless substances, such as pollen or certain foods, while immunosuppression involves a reduction in the efficacy of the immune system, making the body more susceptible to infections but not necessarily leading to an attack on its own cells. Pathogenic infection pertains to diseases caused by microorganisms like bacteria or viruses, which is fundamentally different from autoimmune diseases where the immune response is directed against the body itself.