IgA Deficiency

• Problem: Isolated absence or near absence (< 10 mg/dL) of serum and secretory IgA
• Normal B cells present but don’t make IgA
• Incidence: 1:600
• Most common well-defined primary immunodeficiency
• Inheritance: Thought to be autosomal dominant with variable expressivity (some may be AR)

Presentation:

• Many are asymptomatic
• Recurrent respiratory, GI, and urogenital bacterial infections
• May evolve into Common Variable Immunodeficiency (CVID)

Associations: IgG2 & IgG4 deficiencies, CVID, milk protein allergy, autoimmune diseases, celiac disease

Labs:

• Low IgA; nl IgG and IgM
• 44% have Ab’s towards IgA
• Can have anaphylaxis to blood products/IVIG

Treatment: Supportive

• IVIG not indicated for treatment

also see B-cell defects

CHLA Board Review 2005