Isolated IgA Deficiency
Isolated IgA Deficiency
Updated: 06/02/2020
© Jun Wang, MD, PhD
Definition
- Decreased or absent levels of IgA in the presence of normal levels of IgG and IgM, in a patient older than 4 years old, in whom NO other causes of hypogamamaglobulinemia
General features
- Most common primary immunodeficiency disorder
- Common in whites
- Usually inherited without distinct inheritance pattern
- Sporadic cases associated with drug usages have been reported
- Total (undetectable IgA) or partial (reduced IgA)
- Risk of lymphoid and GI origins malignancies
- May progress to common variable immunodeficiency
Clinical presentations
- Usually asymptomatic
- Symptoms developed in later life
- Recurrent mucosa associated infections, including sinopulmonary and GI tract
- Allegic disorders: atopic dermatitis, respiratory allergies, etc
- Autoimmune disorders, ITP most common
- Anaphylaxis following transfusion of blood or immunoglobulins
Genetic abnormalities
- Variable
- Intrinsic B cell defect
- Dysfunction of Th cell and suppressor T cells
- Abnormality in the cytokines, such as IL-4, Il-6 etc
Pathogenesis
- Defective maturation of IgA producing B cells
- Anti-IgA: Ig-E-mediated anaphylactic reactions upon transfusion of blood products
Key Laboratory findings
- Low IgA, both seral or secretory
- Normal IgG, IgM
Managements
- No treatment if asymptomatic
- Identification of comorbid conditions
- Prevent/treatments of infections
- If transfusion needed, either blood products from an IgA deficient donor, or saline-washed RBC
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