Selective immunoglobulin A deficiency

Selective immunoglobulin A deficiency
The dimeric IgA molecule. 1 H-chain, 2 L-chain, 3 J-chain, 4 secretory component
Specialty	Immunology

Selective immunoglobulin A (IgA) deficiency (SIgAD^[1]) is a kind of immunodeficiency, a type of hypogammaglobulinemia. People with this deficiency lack immunoglobulin A (IgA), a type of antibody that protects against infections of the mucous membranes lining the mouth, airways, and digestive tract. It is defined as an undetectable serum IgA level in the presence of normal serum levels of IgG and IgM, in persons older than 4 years. It is the most common of the primary antibody deficiencies. Most such persons remain healthy throughout their lives and are never diagnosed.