Intravenous immunoglobulin
From Wikipedia, the free encyclopedia
Intravenous immunoglobulin (IVIG) is a blood product mainly used as treatment in two major categories:
- inflammatory and autoimmune diseases,
- immune deficiencies such as X-linked agammaglobulinemia, hypogammaglobulinemia and other diseases featuring low antibody levels.
It contains the pooled IgG immunoglobulins (antibodies) extracted from the plasma of over a thousand blood donors. It is administered intravenously in autoimmune diseases and its effects last between 2 weeks and 3 months.
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[edit] Mechanism of action
The precise mechanism by which IVIG suppresses harmful inflammation is unknown. The donor antibody may bind directly with the abnormal host antibody, stimulating its removal. Alternatively, the massive quantity of antibody may stimulate the host's complement system, leading to enhanced removal of all antibodies, including the harmful ones. IVIG also blocks the antibody receptors on immune cells (macrophages), leading to decreased damage by these cells.
[edit] Uses of IVIG
Diseases in which IVIG is used include:
- multiple sclerosis
- myasthenia gravis
- acute inflammatory polyradiculoneuropathy (AIDP, Guillain-Barré syndrome)
- chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)
- multifocal motor neuropathy with conduction block (MMN)
- immune thrombocytopenic purpura (ITP)
- rheumatoid arthritis
- systemic lupus erythematosus (SLE)
- chronic fatigue syndrome (CFS)
- dermatomyositis and polymyositis
- aplastic anaemia
- asthma (rarely)
- X-linked agammaglobulinemia (XLA)
- common variable immunodeficiency (CVID)
- respiratory syncytial virus (RSV) infection
- Kawasaki disease
In chronic lymphocytic leukemia and multiple myeloma, as well as various rare deficiencies of immunoglobulin synthesis (e.g. X-linked agammaglobulinemia, hypogammaglobulinemia), IVIG is administered to maintain adequate immunoglobulin levels to prevent infections.
[edit] Complications and side effects
Complications of IVIG therapy include
- headache
- dermatitis - usually peeling of the skin of the palms and soles
- infection (such as HIV or viral hepatitis) by contaminated blood product; there is also an as yet unknown risk of contracting variant CJD (vCJD).
- pulmonary oedema from fluid overload, due to the high colloid oncotic pressure of IVIG
- allergic/anaphylactic reactions
- damage such as hepatitis caused directly by antibodies contained in the pooled IVIG
- acute renal failure
- venous thrombosis
- aseptic meningitis
[edit] IVIG Notes
1. IVIG is an infusion of IgG antibodies only. Therefore, peripherial tissues that are defended mainly by IgA antibodies, such as the eyes, lungs, gut and urinary tract are not fully protected by the IVIG treatment.
2. XLA patients are immune to the most virulent adverse effect, anaphylactic shock, as they do not have the antibodies to react against the treatment. Anaphylactic shock has a higher chance to occur in IgA deficient patients which do have other antibody types.
3. In case of reoccurring side effects, it is recommended to slow the pace of the IVIG administration and to reduce the dosage. It is also advisable to change IVIG brand, as some people react against to a specific brand.
4. If the patient is diabetic, he should take into consideration the medium in which the antibodies are solubilized in the IVIG treatment, as some brand solubilize antibodies with high concentrated sugars (such as sucrose and maltose).
5. FDA guidelines for IVIG state the product should be:
- Prepared out of at least 10,000 different human donors.
- All four IgG subgroups (1-4) should be present.
- The IgG should maintain biological activity and lifetime of at least 21 days.
- Does not contain samples which are HIV, hepatitis B, hepatitis C positive.
- Screened and treated in an manner that destroys viruses.
6. IVIG is also considered a modulator of the immune system and was shown to be beneficial in treating numerous autoimmune diseases such as rheumatoid arthritis (RH), lupus (SLE), multiple sclerosis (MS), myasthenia gravis, pemphigus, polymyositis (PM), dermatomyositis (DM), granulomatosis (WG), Churg-Strauss syndrome, chronic infammatory demyelinating polyneuropathy and more.
7. IVIG can be given to pregnant women.
8. IVIG is also used as a treatment for unexplained reoccurring miscarriages. The effectiveness of the therapy is controversial.
