Selective IgA deficiency is one of the most common types of PI. These individuals lack IgA, but usually have normal amounts of other immunoglobulins (antibodies). Many people go undiagnosed because they are never sick enough to be seen by a doctor, while others may develop a variety of severe problems.
Selective IgA Deficiency
IgA protects the body at surfaces that come in contact with the environment. These sites are the mucosal surfaces—mouth, ears, sinuses, nose, throat, airways within the lungs, gastrointestinal tract, eyes, and genitals.
IgA antibodies are transported in secretions to these mucosal surfaces and play a role in protecting them from infection, which is why IgA is known as a secretory antibody. Because the area of a person's mucosal surfaces is equal to 1.5 tennis courts, the importance of IgA in protecting these surfaces cannot be overstated.
Although people with selective IgA deficiency do not produce IgA, they do produce all the other immunoglobulins. In addition, the other aspects of their immune systems function properly.
The causes of selective IgA deficiency remain unknown. It is likely there are a variety of causes that vary from person to person.
Low serum IgA, like absent serum IgA, is relatively common. Most people with low serum IgA have no apparent illness; others have symptoms similar to