Intravenous immunoglobulin
Introduction
Intravenous immunoglobulin (IVIG) is a blood product administered intravenously. It contains the pooled, polyvalent, IgG (immunoglobulin (antibody) G) extracted from the plasma of over a thousand blood donors. IVIG's effects last between 2 weeks and 3 months. It is primarily used as treatment in three major categories: immune deficiencies, autoimmune diseases, and acute infections.
History
The use of plasma as a component of blood to be transfused was pioneered by Dr. Charles R. Drew in the early 20th century. However, it was not until the 1950s that Dr. Ogden Carr Bruton, a pediatric immunologist, discovered the medical use of immunoglobulin by intravenous route for the treatment of immune deficiencies.
Composition
IVIG is derived from the plasma of thousands of donors and contains the typical IgG antibodies found in the normal population. It is prepared from large pools of human plasma collected from several thousand blood donors, typically containing more than 95% unmodified IgG, which has intact Fc-dependent effector functions and only trace amounts of IgA or IgM.
Mechanism of Action
The exact mechanism of action of IVIG is unclear. It is thought to work via several mechanisms including: neutralizing pathogenic autoantibodies; enhancing the expression of the inhibitory Fc receptor on macrophages; providing anti-idiotypic antibodies; suppressing inflammatory cytokines; and modulating dendritic cell function.
Medical Uses
IVIG is used in the treatment of various diseases, primarily immune deficiencies, autoimmune diseases, and acute infections. It is also used in some treatment protocols for secondary immune deficiencies resulting from diseases such as HIV/AIDS, leukemia, and multiple myeloma.
Side Effects
The most common side effects of IVIG are headache, fever, chills, flushing, dizziness, fatigue, malaise, and changes in blood pressure. Severe reactions, although rare, may include anaphylaxis or transfusion related acute lung injury.
Production
The production of IVIG involves several steps: plasma collection, cold ethanol fractionation, purification, and viral inactivation. The process is designed to maintain the integrity of the IgG molecules and to minimize the presence of other plasma proteins.
Administration
IVIG is administered intravenously. The dose and frequency of IVIG administration is dependent on the condition being treated and the patient's individual response to therapy.