Immune system disorders occur when the body's defense system, which protects against infections and diseases, does not function properly. These disorders can be classified into two main categories: autoimmune diseases, where the immune system mistakenly attacks healthy cells, and immunodeficiency disorders, where the immune system is weakened and unable to fight off infections effectively. Examples of autoimmune diseases include rheumatoid arthritis and lupus, while HIV/AIDS is a well-known immunodeficiency disorder. Symptoms of immune system disorders can vary widely, depending on the specific condition. Common signs may include frequent infections, fatigue, joint pain, and skin rashes. Diagnosis often involves blood tests and medical history assessments. Treatment options may include medications to suppress the immune response or therapies to boost immune function, depending on the type of disorder.