Overview

Immunoglobulin (also called gamma globulin or immune globulin) is a substance made from human blood plasma. The plasma, processed from donated human blood, contains antibodies that protect the body against diseases. When you are given an immunoglobulin, your body uses antibodies from other people's blood plasma to help prevent illness. And even though immunoglobulins are obtained from blood, they are purified so that they can't pass on diseases to the person who receives them.

Specific types of immunoglobulin are made to protect against specific diseases, such as hepatitis, chickenpox, or measles. Immunoglobulin injections may:

• Give short-term protection against or reduce the severity of certain diseases.
• Protect your fetus if you are pregnant and at risk for Rh sensitization.
• Decrease the immune system's ability to attack body tissues in some cases of autoimmune disease.
• Help people who have an inherited problem making their own antibodies or those who are having treatment for certain types of cancer (such as leukemia). Treatments for some cancers can cause the body to stop producing its own antibodies, making immunoglobulin treatment necessary.

Disease prevention

You may be given an immunoglobulin if you are exposed to certain infectious diseases, such as hepatitis A, rubella, or measles. The immunoglobulin may prevent or reduce the severity of the illness if given shortly after exposure. The time period during which an injection provides this benefit ranges from days to months, depending on the disease.

Immunoglobulins do not provide long-term protection in the same way as a traditional vaccine. The protection they provide is short-term, usually lasting a few months. It is still possible to get the disease after the immunoglobulin has worn off.

Rh sensitization

When an Rh-negative woman becomes pregnant with an Rh-positive fetus (which can occur when the father's blood is Rh-positive), the pregnant woman's immune system produces antibodies that can destroy the fetus's blood in a future pregnancy. This antibody response is called Rh sensitization and occurs only if the fetus's blood mixes with the pregnant woman's, which can happen during birth.

To prevent Rh sensitization during pregnancy, you must have an Rh immunoglobulin injection if you are Rh-negative. This is done during your pregnancy and after delivery to protect the fetus of a future pregnancy.

Idiopathic thrombocytopenic purpura (ITP)

Immunoglobulin is sometimes used to treat idiopathic thrombocytopenic purpura (ITP), an immune disorder in which the body attacks the cells responsible for blood clotting (platelets), resulting in bleeding. The cause of ITP is not known (idiopathic).

People with this disorder may have bruises or black-and-blue marks (purpura) on the skin. Internal bleeding is a more serious complication that can occur.

Some cases of ITP may go away on their own and do not require treatment. In other cases, treatment may be needed to control bleeding. Some medicines can help the body make more platelets. Steroid medicine (such as prednisone) also may be needed to suppress the immune system. An intravenous (IV) infusion of a substance made from human blood plasma (immunoglobulin) may be given. Sometimes it is necessary to have platelet transfusions. In rare cases, the spleen may need to be removed.