IVIg

Intravenous immunoglobulin (IVIG) is a sterile, ready-to-use product derived from the pooled plasma of thousands of healthy donors. It contains concentrated immunoglobulin G (IgG) antibodies and is used to provide passive immunity and to modulate immune function in a range of conditions. IVIG products are screened and processed to reduce the risk of infectious disease transmission, but residual risks remain.

The mechanism of action of IVIG is not completely understood and is thought to involve several pathways. These include neutralization of circulating autoantibodies, blockade of Fc receptors on phagocytes, modulation of the complement system, provision of anti-idiotypic antibodies, and broader effects on cytokine production and B and T cell activity. The result is reduced autoantibody activity and altered immune responses in inflammatory and autoimmune disorders.

Indications for IVIG fall into two broad categories: replacement therapy for primary (and some acquired) antibody deficiencies, where IVIG supplies missing IgG to prevent infections (for example, X-linked agammaglobulinemia, common variable immunodeficiency); and immunomodulatory treatment for autoimmune and inflammatory diseases. Commonly treated conditions include immune thrombocytopenia, Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and Kawasaki disease in children. It is also used in certain dermatologic and hematologic conditions and in some transplant settings, depending on clinical judgment and guidelines.

Administration involves intravenous infusion, typically over several hours, with dosing and frequency varying by indication. Patients are monitored for infusion-related reactions and potential adverse effects, including headaches, fever, aseptic meningitis, thromboembolism, kidney injury, and, in those with IgA deficiency, anaphylaxis risk.