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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