From the Guidelines
Immunoglobulins (Ig) are specialized proteins produced by the immune system that function as antibodies to identify and neutralize foreign substances like bacteria, viruses, and other pathogens. They are crucial for immune protection and come in five main classes: IgG, IgM, IgA, IgE, and IgD, each with distinct roles 1.
Key Characteristics of Immunoglobulins
- IgG is the most abundant antibody in blood and tissue fluids, providing long-term immunity against infections.
- IgM appears early in infection and is effective at activating complement, a cascade of immune proteins.
- IgA predominates in mucous secretions, protecting body surfaces like the respiratory and digestive tracts.
- IgE is involved in allergic reactions and parasite defense, while IgD functions primarily on B cell surfaces.
- Immunoglobulins have a characteristic Y-shaped structure with variable regions that recognize specific antigens and constant regions that determine their class and biological functions.
Clinical Use of Immunoglobulins
Intravenous immune globulin (IGIV) is a product derived from blood plasma, used for replacement therapy in primary antibody-deficiency disorders, treatment of Kawasaki disease, immune thrombocytopenic purpura, hypogammaglobulinemia in chronic lymphocytic leukemia, and some cases of HIV infection 1. The efficacy of IVIG in reducing coronary artery abnormalities in Kawasaki disease is well established, with a recommended dose of 2 g/kg as a single infusion 1. IVIG has a generalized anti-inflammatory effect, with possible mechanisms including modulation of cytokine production, neutralization of toxins, and augmentation of regulatory T-cell activity 1.
Important Considerations
- IVIG is made from pooled donor plasma, and product manufacturing differences may exist, potentially affecting adverse effects 1.
- Measles, mumps, and varicella immunizations should be deferred for 11 months after receiving high-dose IVIG 1.
- Despite treatment with high-dose IVIG, some children may still develop coronary artery dilation or aneurysms 1.
Overall, immunoglobulins play a vital role in immune protection, and their clinical use, particularly IVIG, is crucial in the management of various diseases 1.
From the Research
Definition and Function of Immunoglobulins
- Immunoglobulins, also known as antibodies, are large Y-shaped proteins produced by B-cells and plasma cells that are used by the immune system to identify and neutralize foreign objects such as bacteria and viruses 2.
- They play a crucial role in the immune system by binding to specific antigens, helping to remove pathogens from the body.
Types and Uses of Immunoglobulins
- Immunoglobulin G (IgG) preparations are approved by the US Food and Drug Administration for the treatment of primary immunodeficiency disease, idiopathic thrombocytopenic purpura, Kawasaki disease, chronic lymphocytic leukemia with frequent infections, bone marrow transplantation, to prevent infection in pediatric human immunodeficiency virus, and chronic inflammatory demyelinating polyneuropathy 2.
- Intravenous immunoglobulin (IVIg) is used for many immune-deficient conditions and autoimmune conditions, including Kawasaki disease, where it is critical for control of inflammation 3.
Mechanism of Action and Therapeutic Uses
- The mechanism of action of IVIg in Kawasaki disease is not fully understood, but it is thought to involve the inhibition of interaction between natural killer cells and endothelial cells 4.
- IVIg is a safe and effective therapeutic modality that can be added to the repertoire of various agents used to treat autoimmune and systemic inflammatory diseases 5.
- The use of IVIg in combination with other treatments, such as corticosteroids, may improve outcomes in certain conditions, such as Kawasaki disease 6.