Immunoglobulin (Ig) is a sterilized solution obtained from pooled human blood plasma, which contains the immunoglobulins (or antibodies) to protect against the infectious agents that cause various diseases. Antibodies are substances in the blood plasma that fight infections. Our bodies create antibodies (or immunity) against disease-causing agents when infections occur. These antibodies can protect us from becoming ill if we are exposed to the same infectious agents sometime in the future. When someone is given IG, that person is using other people's antibodies to help fight off or prevent an illness from occurring. This protection is temporary and should not be confused with getting an immunization, which provides longer-term protection. Special IG formulations are produced from donors with high levels of antibodies against hepatitis B (Hepatitis B Immune Globulin-HBIG), rabies (Rabies Immune Globulin-RIG), tetanus (Tetanus Immune Globulin-TIG) and varicella (chickenpox)(Varicella Zoster Immune Globulin-VZIG). Immunoglobulins are sometimes called gamma globulins or immune serum globulins.
Why are they used?
Immunoglobulin is a sterile solution of globulins containing many antibodies normally present in human blood which is used to provide passive immunization for persons exposed to diseases such as infectious hepatitis, poliomyelitis, mumps, rubella (German measles), rubella (measles) and varicella (Chicken pox). All antibodies are protein blood fractions called immune globulins.
There are five classes of immunoglobulins with distinct physical and functional properties:
1. IgG is the principle immunoglobulin in human serum and accounts for approximately 80% of the total immunoglobulins in the blood. These molecules effectively penetrate extravascular spaces and readily cross the placental barrier to provide passive immunity to the newborn.
2. IgA which comprises about 13% of plasma immunoglobulins is the principle antibody in saliva, tears, colostrums and fluids of the gastrointestinal, respiratory and urinary tracts. Their main function may be to prevent foreign substances from adhering to mucosal surfaces and entering the blood.
3. IgD (Rhogam) is an immune globulin preparation that suppresses the immune response to non-sensitized Rh(D) negative individuals who receive Rh(D) positive blood as a result of the fetomaternal transfusion (as a consequence of abdominal trauma, amniocentesis, abortion, or full term delivery) or due to a transfusion error. A pregnant woman who is RH negative, may become sensitized by blood of an Rh+ fetus. In subsequent pregnancies, if the fetus is Rh+, Rh antibodies produced in maternal blood may cross the placenta and destroy fetal cells, causing erythroblastosis fetalis ( a hemolytic disease of the newborn marked by anemia, jaundice, enlargement of the liver and spleen.)
4. IgM comprises approximately 6% of the total plasma immunoglobulins in a normal adult. This immunoglobulin represents the predominant class formed during a primary immune response, but is stabilized rapidly, with a plasma half-life of only 6 days.
5. IgE normally only 0.004% of the total plasma immunoglobulin is known as the reaginic antibody. However, it may rise 5 to 20 times normal when the patient has a parasitic infestation and/or in some children with chronic atopic diseases.
How are they prepared?
Immunoglobulin preparations, plasma proteins that regulate and mediate normal body function as well as being markers of disease and monitors of changing health, are produced by cold alcohol precipitation of large pools of human plasma. This preparation is heated for at least 10 hours at 60 degrees centigrade to inactivate contaminating viruses.
Administration and Dosage
1. Rh immune globulin is administered to the mother by IM (Intramuscular) injection. It should not be administered intravenously or given to the infant.
2. Intravenous immunoglobulins are used for treatment of primary immunodeficiencies, pediatric AIDS, marrow transplantation, lymphocytic leukemia, immune thrombocytic purpura, etc.
3. Dosing depends on type and severity of the disease. Consult physician for appropriate dosing.
Immunoglobulin is a plasma protein fraction. The use of immune globulins is a personal choice.
Watchtower, June 15, 2000
Watchtower June 1, 1990, pages 30-31
Awake, December 8, 1994, pages 23-27
Winrobe's Clinical Hematology, 10th Edition, Volume 1, page 576
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