What describes autoimmune diseases?

Autoimmune diseases are characterized by the immune system erroneously targeting and attacking the body's own cells, tissues, or organs, mistaking them for foreign invaders. This misrecognition leads to an inappropriate immune response as lymphocytes, which include T cells and B cells, become activated against self-antigens. In these conditions, the body is effectively fighting against itself, which can result in inflammation and damage to various body systems.

The correct answer highlights this fundamental aspect of autoimmune diseases, providing insight into both the underlying mechanism and the consequences of such immune dysfunctions. Understanding this helps in appreciating how the body's immune response, which is normally protective, can become harmful in the case of autoimmune disorders.