Immune system diseases occur when the body's defense system, which protects against infections and diseases, malfunctions. This can lead to conditions where the immune system attacks healthy cells, known as autoimmune diseases, or fails to respond adequately, resulting in immunodeficiency disorders. Examples include rheumatoid arthritis and HIV/AIDS. These diseases can cause a range of symptoms, depending on the specific condition and the body parts affected. Treatment often involves medications to manage symptoms and improve immune function. Early diagnosis and intervention are crucial for better outcomes in individuals with immune system diseases.