Lab

Immunoglobulin A

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Immunoglobulin A, IgA Immunoglobulin, Gamma Globulin A, IgA

  • Lab
  • Normal
  1. Range: 50-350 mg/dl
  2. Varies by age
  • Physiology
  1. Subclasses IgA1, IgA2
  2. Dimer (2 Antibody molecules joined by j-chain) when secretory Ig with Molecular weight 350,000 dalton
  3. Accounts for 10-15% of all Antibody
  4. Serum half life of 6 days
  5. Present in body secretions (e.g. tears, Saliva, milk) and responsible for mucosal Immunity
  • Causes
  • Increased IgA
  1. Lymphoproliferative disorders (e.g. Multiple Myeloma)
  2. Berger's Disease (IgA nephropathy)
  3. Chronic infection
  4. Autoimmune disorders
  5. Liver disease (e.g. Portal Cirrhosis)
  6. Henoch Schonlein Purpura
  • Causes
  • Decreased IgA
  1. IgA Hypogammaglobulinemia
  2. Protein losing Enteropathy
  3. Hereditary Ataxia and telangiectasia
  4. Nephrotic Syndrome
  • References
  1. Bakerman (1984) ABCs of Lab Data, p. 252-3
  2. Immunoglobulin M (IgM)
    1. Pentamer (5 Antibody molecules) when secretory Ig with Molecular weight 900,000 dalton
    2. Responsible for early, primary Antibody response
  3. Immunoglobulin E (IgE)
    1. Long stem (Fc) monomeric Antibody with Molecular weight 180,000 dalton
    2. Serum half-life of 2.5 days
    3. Reacts to allergans (Type 1 Hypersensitivity) and Parasitic Infections
  4. Immunoglobulin D (IgD)
    1. Monomer with Molecular weight 160,000 dalton
    2. Serum half life of 3 days
    3. Membrane bound surface Antibody