White blood cells, antibodies, and other components, including organs and lymph nodes, make up the body’s immune system. Many disorders can weaken the immune system and cause a person to become immunocompromised. These immunodeficiency disorders, which range from mild to severe, can be present from birth or may occur as a result of environmental factors. They include:
Sometimes, an immunodeficiency disorder can be so mild that a person may not be aware of it for years. Other times, the disorder is more severe and causes a person to experience frequent infections throughout their life.