Primary immunodeficiency

Immunodeficiencies are a broad class of conditions where one or more components of the immune system are missing. A person with an immunodeficiency has trouble fighting infections. They may contract more illnesses than other people, and may become infected with microbes that do not normally cause disease in humans.

When someone is born lacking a component of the immune system, it is termed ‘primary immunodeficiency’.

Secondary immunodeficiency describes immunodeficiencies arising as the result of another event such as HIV infection or taking immune suppressing medication.

The Immune Deficiencies Foundation Australia provides information and support for people with immunodeficiencies, their carers and relatives.

Many primary immunodeficiencies are caused by changes in the genes that contribute to immune cell development and function. This means they can be passed from parents to a child, or can occur frequently in an extended family.

Common variable immunodeficiency (CVID) is the most common primary immunodeficiency, both in Australia and worldwide. It is estimated that approximately one in 10,000 Australians have CVID.

People with CVID have problems making antibodies, which are important in fighting infections and building immune protection. Low levels of antibodies put people with CVID at risk of recurrent bacterial infections. These people are also unable to develop a normal immune response to vaccines.

Diagnosing CVID is difficult and requires exclusion of other primary immunodeficiencies. As symptoms of CVID can be quite different between people, many people with this condition are not diagnosed until they are adults.

CVID appears to be caused by faulty genes. However, it appears there are many different genes that can contribute to CVID. Only in a few cases have the gene changes causing CVID been identified. For most people, the underlying cause of CVID is not known.

Our research into CVID aims to find the underlying cause of CVID. To do this we need help from people with CVID, as well as people with another immune deficiency called X-linked agammaglobulinemia (XLA). Find out more about our study into the causes of CVID.

Around a quarter of people with CVID have autoimmune diseases. This suggests that the cause of CVID could be part of a broader problem with the control of the immune system, where appropriate immune responses to microbes are stifled, but harmful attacks on normal body tissues occur.