One of the most important functions of the body's normal immune system is protect agains infection.
Although everyone experiences infections of one form or another, some people have infections that seem to fall beyond the scope of normal immue defence.
Such cases may be explained by inherited defect of the immune system, known as Primary Immune Deficiency (PID). Many of these rare diseases appear in childhood but some emerge for the first time in adulthood.
More than 200 are recognised by the World Health Organisation. The disorders range widely in severity but share a common pattern:
Disorders generally show as a repeated "ordinary" infections, often of the sinuses, ears or lungs. They can also cause gastrointestinal problems or inflammation of the joints.
Infections can be chronic requiring long courses of antibiotics.
Disorders affect males and females of any age.
Early diagnosis and treatment of disorders is essential to prevent the recurring infections from causing permanent damage.
The incidence of PID varies across the various disorders. Some disorders are relatively common, affecting 1:500 people. Others a much rarer, afttecting less than 1:250,000 people. PID Facts PID affects at least 10 million people worldwide. Source: US Department of Health and Human Services. National Institute of Health 2009 Can affect anyone, regardless of age and sex Vary in severity depending on whether one or several parts of the immune system are affected It is estimated that 70 - 80% of PID's remain undiagnosed globally. Source: American Association for the advancement of Science 2007 Unlike many other rare disorders, PIDs can be successfully treated.
Primary immune deficiency diseases such Common Variable Immune Deficiency (CVID) are caused by defects in the development and maturing of cells in the immune system and are usually inherited.
These diseases are called primary immunodeficiencies because no other causes for the immunodeficiency such as infections, drugs or toxins can be identified.
CVID is one of the more common primary immune deficiency disease and affects both males and females.
The full cause of autoimmune diseases are not yet known. However, in many cases it appears that theere is some inherited tendency to develop autoimmune diseases. In people with this inherited tendency, other factors such as infections and some drugs may play a role in triggering autoimmune disease.