Common Immune System Disorders While the immune system is designed to protect the body, it does not always function perfectly. Immune system disorders occur when immune responses are either too weak or too strong. Immunodeficiency disorders result from a weakened immune system. People with these conditions are more vulnerable to infections. Some immunodeficiencies are inherited, while others develop due to illness, medications, or aging. Autoimmune diseases occur when the immune system mistakenly attacks healthy cells. Conditions such as rheumatoid arthritis, lupus, and type 1 diabetes fall into this category. Allergies are another form of immune overreaction. The immune system responds…