IgA Deficiency

Most common immunodeficiency disorder.

Incidence estimated to be 1:100 to 1:1000.

More prevalent among European descendants.

Most pts are clinically normal.

Increased risk of allergies and anaphylaxis.

Increased risk of malignancies.

Increased incidence of pulm complications, atopic disorders, and postop infections

Recurrent sinopulmonary infections leading to decreased pulm reserve

Associated autoimmune disorders (e.g., lupus, DiGeorge syndrome)

Associated GI disorders leading to volume depletion

Anaphylactic reactions from transfusion of blood products containing IgA

An immunodeficiency syndrome with increased susceptibility to nosocomial infection.

Cell-mediated immunity is usually normal.

Coexisting diseases may include atopy, recurrent sinopulmonary infection, GI disease, and autoimmune disease.

Decreased synthesis or secretion of IgA.

Absence of IgA on mucosal surface.

Decreased IgA blocking antibodies against environmental antigens.

Associated with histocompatibility groups HLA-A1, HLA-B8, and HLA-Dw3.

There have been several reported cases of acquired IgA deficiency.

Usually decreased rather than absent lymphocyte IgA secretion.

Overt clinical disease presentation may relate to changes in IgG subclass and/or compensatory IgM secretion.