http://www.nichd.nih.gov/publications/pubs/primary_immuno.cfm
National Institute of Child Health and Human Development Information Resource Center
Some people are born with an immune defense system that is faulty. They are missing some or, in the worst cases, almost all of the body’s immune defense weapons. Such people are said to have a primary immunodeficiency (PI). This page includes an overview of symptoms, diagnosis, and treatment.