Definition: Primary Immune Deficiency Disease (PIDD) is a genetic disorder in which some part of the immune system does not function properly. There are many different types of PIDD, depending on the particular part of the immune system affected. Primary Immune Deficiency Disease differs from Acquired Immune Deficiency (AIDS) in that the condition is present from birth and involves a part of the immune system being broken.


It is not contagious. For more information on Primary Immune Deficiency Disease, visit About.comPediatrics or one of these dedicated sites:

• Immune Deficiency Foundation
• Primary Immunodeficiency Resource Center
• ImmuneDisease.com
• International Patient Organisation for Primary Immunodeficiencies

Alternate Spellings: Primary Immunodeficiency (PI)