IMMUNOGLOBULIN REPLACEMENT THERAPY FOR PRIMARY IMMUNODEFICIENCIES
Dr Ira Shah
Consultant Pediatrician, Nanavati Hospital and B.J.Wadia Hospital for Children, Mumbai
Editor - Pediatric Oncall
What are immunoglobulins?
Immunoglobulins are also called as antibodies. They are special proteins formed by the B-lymphocytes that attach to a microorganism and help to kill the germ by easy ingestion by phagocytes.
What is immunoglobulin replacement therapy?
Individuals who are unable to produce adequate amount of immunoglobulins or antibodies such as patients with X-linked agammaglobulinemia, common variable immunodeficiency, Hyper IgM syndrome or other forms of hypogammaglobulinemia may benefit from immunoglobulin replacement therapy. Immunoglobulins are pooled from blood donated by several individuals. The extracted immunoglobulin is purified and carefully screened for diseases such as AIDS, hepatitis. Any sample that is suspected to have any of these diseases is discarded. The purified immunoglobulin finally contains only immunoglobulin a (IgG) class and only traces of IgA and IgM. These immunoglobulins are then injected intravenously (directly into the vein) or are given subcutaneously (directly under the skin).
How are patients with primary immunodeficiency disorders (PID) given immunoglobulins?
Most antibodies (over ½ of the infused antibodies) are used up the body in 3-4 weeks. So in patients with PID, since the patient's own immune system is preparing inadequate quantity of antibodies, these antibodies are infused at regular intervals to prevent infection. This may be in form of weekly infusions subcutaneously and once every 3-4 weeks intravenously. Immunoglobulin replacement therapy is these patients is usually required life long.
Are there any side effects of immunoglobulin therapy?
Most of the immunoglobulins that can be given intravenously contain some type of sugar or amino acids as preservative. This can lead to high blood sugars in some patients. Most patients have no side effects from IV infusions, but sometimes low grade fever or headache occur. Sometimes, allergic reactions (especially in patients with IgA deficiency) in form of hives, wheezing or chest pain can occur that responds to antihistamines.
Which is the best route of administration of immunoglobulin replacement therapy?
IV infusions are usually given once in 3-4 weeks. It allows larges dose of immunoglobulin to be given thus the IgG levels in the blood are kept in normal range till the next dose is due. The infusion usually takes 2-4 hours and can be given in an outpatient clinic.
Subcutaneous infusion can be an alternative for patients who have side effects to intravenous immunoglobulin. Since small doses are given, the dosing is required more frequently (once a week). It can be given at home by inserting a needle and attaching it to a small pump that can be worn on the belt.
Last updated on 26-3-2011