Mechanism of Action of IVIG in ITP
Primary Mechanism: Fc Receptor Blockade
- The American Society of Hematology suggests that IVIG may modulate autoantibody production, interfere with B-cell function, and autoantibody synthesis, though this is a secondary effect 1
- The American Society of Hematology proposes that IVIG may contain antibodies that neutralize anti-platelet autoantibodies through anti-idiotypic antibodies 1
- The American Society of Hematology indicates that IVIG can interfere with complement-mediated platelet destruction through complement modulation 1
Clinical Implications of the Mechanism
- The American College of Physicians recommends that the mechanism of action of IVIG explains why it produces rapid clinical responses, typically within 24 hours, compared to other ITP treatments, due to the immediate blockade of Fc receptors 1
- The American Society of Hematology states that the standard dose of 1 g/kg IVIG is designed to achieve sufficient Fc receptor saturation to block platelet clearance, with higher total doses producing more rapid and pronounced platelet count increases 2
Enhancement with Corticosteroids
- The American Society of Hematology suggests that concomitant corticosteroids may enhance the IVIG response through complementary mechanisms, such as suppressing autoantibody production and reducing macrophage activity 1