What collection of autoimmune diseases involves the immune system attacking healthy tissues?

The correct answer is lupus, which is also known as systemic lupus erythematosus. This autoimmune disease is characterized by the immune system erroneously attacking the body's own healthy tissues, leading to widespread inflammation and damage to various organs and systems. In lupus, this inappropriate immune response can affect many areas, including the skin, joints, kidneys, and even the heart and lungs.

While rheumatoid arthritis, multiple sclerosis, and Hashimoto's thyroiditis also involve the immune system attacking the body’s own tissues, lupus is unique in its systemic nature and the variety of symptoms it manifests as a result of this attack. It's commonly referred to as a "great imitator" because it can mimic other illnesses and has a wide range of symptoms, making it a complex disease to diagnose and manage.

Rheumatoid arthritis primarily affects the joints, while multiple sclerosis primarily targets the nervous system. Hashimoto's thyroiditis specifically attacks the thyroid gland. Each of these conditions demonstrates autoimmune behavior, but lupus stands out for its comprehensive impact on the body and its diverse clinical presentation.