Immunoglobulin Replacement Therapy in Primary Immunodeficiencies

Immunoglobulin (antibody) replacement therapy (IRT) is one of the most effective and commonly used therapies for some primary immunodeficiency diseases (PIDs).  Many people with PIDs have insufficient antibodies to adequately fight infections, and this therapy can be life saving.   

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Why is IRT used?

In people with PIDs, IRT can: 

  • Treat existing infections
  • Prevent new infections from occurring

How is IRT made?


How is IRT given?

There are two ways that IRT can be given: 

  • Intravenous immunoglobulin (IVIG) infusions are delivered directly into the person's vein, usually in a hospital day clinic. The infusion can take approximately 2 to 4 hours. The dose and frequency vary, and depend on the person's weight and immunoglobulin levels. Most people receive IVIg doses once every month.
  • Subcutaneous immunoglobulin (SCIg) - This involves slowly infusing the antibody preparation directly under the skin, which can be done at home, often by using a pump. This is usually done once or more each week, as only 10-15mL can be infused into any one site. A 10mL infusion can be delivered in half an hour. It may be necessary in some cases for infusions to be more frequent, particularly during introduction to therapy. When beginning SCIg therapy, red lumps may form under the skin. These usually disappear quite quickly and after a few weeks of therapy usually stop appearing.     

Are there any side effects of IRT?

IRT is normally very well tolerated and serious side effects are very rare.  However, there are some side effects that people receiving IRT should be aware of:

  • Risk of blood-borne infections
  • Other side effects
    Some people get minor side effects such as low grade fevers or headaches, which can usually be reduced by a slower infusion rate or treated with paracetamol. Occasionally people experience hives or wheezing or rarely severe headaches. Severe allergic reactions and abnormal kidney function due to IRT are rare.
  • IgA reactions
    In rare cases, when a person lacks Immunoglobulin A (IgA) antibodies, reactions similar to severe allergic reactions may occur when receiving blood products containing IgA. However, most IgA deficient people receive blood products without difficulty. These reactions are less likely with current IgA depleted Immunoglobulin products.


Limitations of IRT

IRT does not cure the antibody deficiency, and does not usually reverse long term organ injury from chronic infections. IRT contains only one of the important components of the immune system's response to infection. For these reasons it is best to start IRT before organ damage has occurred.

Availability of IRT



IRT is reserved for those people with confirmed abnormalities in antibody production, and who experience recurrent infections.


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Content last updated March 2019