Primary antibody deficiencies

Primary antibody deficiencies are the most common primary immunodeficencies. You probably have many questions about what your condition means. What causes primary antibody deficiency (PAD)? How is it treated? What effect does it have on your everyday life?

Why does primary antibody deficiency occur?

PAD results from the failure by your immune system to produce sufficient antibodies in the bloodstream to fight infections, particularly those caused by bacteria.

Why are antibodies important?

Antibodies do two things.

  • They help us to recover from an infection.
  • They prevent the same infection from recurring in the future.

Antibodies are members of a family of proteins called immunoglobulins (Ig). You may also have heard of the term gammaglobulins, which was used to describe these proteins until researchers found that they were part of the immune system.
Antibodies are divided into three main classes: G, A and M. The most abundant class is G. It is divided into four subclasses.

Each class of antibody has a different function. For example, IgA antibodies protect body surfaces such as the lining of the lungs, and IgG antibodies are found in blood and tissue fluid and protect against invading infections.

Antibodies normally get into all parts of the body, including the skin, eyes, ears, nose, throat, lungs, intestines, joints, and against invading organisms. So, any part of the body can be affected by primary antibody deficiency, although usually only a few parts are affected in each case.

This page was reviewed by the Medical Advisory Panel April 2013.