What is IVIG (Intravenous Immunoglobulin)?

Intravenous Immunoglobulin (IVIG): Definition and Clinical Applications

IVIG is a blood product prepared from the pooled plasma of thousands of donors that contains concentrated immunoglobulin G (IgG) antibodies and is administered intravenously to treat various autoimmune, inflammatory, and immunodeficiency conditions. 1, 2

Mechanism of Action

IVIG works through multiple immunomodulatory mechanisms:

• Provides a broad spectrum of opsonizing and neutralizing IgG antibodies against bacterial and viral agents 2
• Exerts anti-inflammatory effects through:
  • Modulation of cytokine production
  • Neutralization of toxins or pathogenic agents
  • Augmentation of regulatory T-cell activity
  • Suppression of antibody synthesis
  • Blockade of Fc-γ receptors
  • Inhibition of the complement system
  • Provision of anti-idiotypic antibodies 1

Standard Dosing Regimens

IVIG dosing varies by indication:

• Kawasaki Disease: 2 g/kg as a single infusion over 10-12 hours with aspirin 1
• Primary Immunodeficiency: 300-600 mg/kg every 3-4 weeks 2
• Immune Thrombocytopenic Purpura: 0.4 g/kg/day for 5 days or 1 g/kg/day for 1-2 days 1
• Autoimmune/Inflammatory Conditions: Typically 2 g/kg divided over several days, given at monthly intervals 1

Clinical Applications

IVIG is used in numerous conditions including:

1. Kawasaki Disease: Reduces prevalence of coronary artery abnormalities 1
2. Primary Immunodeficiency Disorders: Replacement therapy 2
3. Immune Thrombocytopenic Purpura: Increases platelet counts 1
4. Guillain-Barré Syndrome and Chronic Inflammatory Demyelinating Polyneuropathy: Modulates immune response 1
5. Antibody-Mediated Rejection in Transplantation: Inhibits HLA-specific alloantibodies 1
6. Dermatomyositis: Treatment for refractory disease 3
7. Pemphigus Vulgaris: For severe or refractory cases 1
8. Immunotherapy-related toxicities: Management of certain immune-related adverse events 1

Adverse Effects

Common and serious adverse effects include:

• Common: Headache, fever, chills, fatigue, nausea, myalgia 1
• Less Common: Aseptic meningitis, hemolytic anemia (especially in individuals with AB blood type) 1
• Rare but Serious: Thrombosis, renal failure, anaphylaxis (particularly in IgA-deficient patients), intravascular hemolysis 1, 2

Important Clinical Considerations

• IVIG is a biological product made from pooled donor plasma with product manufacturing differences that may affect adverse effect profiles 1
• Live vaccines (measles, mumps, varicella) should be deferred for 11 months after receiving high-dose IVIG 1
• Patients with selective IgA deficiency and detectable IgA antibodies may be at risk for anaphylactic reactions 4
• Pre-medication with acetaminophen or corticosteroids may reduce infusion reactions 1
• Half-life of IVIG is approximately 30-32 days 2

Monitoring

• Monitor for infusion reactions during administration
• For patients receiving regular IVIG for immunodeficiency, trough IgG levels should be monitored
• Renal function, complete blood count, and signs of thrombosis should be monitored in patients receiving high-dose therapy 2

IVIG represents a valuable therapeutic option for numerous conditions, with its efficacy well-established in several autoimmune and inflammatory diseases. The appropriate dose and administration schedule should be determined based on the specific indication and patient characteristics.