A disease state that may be present in any age group, primary immunodeficiency is often undiagnosed for long periods of time because it is masked by a wide variety of clinical symptoms.
The major role of the immune system is the defense of the host, and its most important function is the fight against infection. When part of the immune system is absent or its function is impaired, an immunodeficiency disease may occur.
Primary Immunodeficiencies (PID) are mostly due to genetic disorders, a mutation in genes coding for immune system components. It is often an inherited disorder. Infants are born with the disease although it may not be apparent until adulthood. It is therefore important to consider PID as a diagnosis for patients of all ages - babies, children and adults.
A patient with PID may present with a variety of clinical symptoms which are treated by the clinician.
- Recurrent infections throughout life due to common or rare pathogens.
- Severe infections that require intensive treatment and often hospitalization or lead to lifelong disability or, rarely, death.
- Persistent infections in patients that do not respond to antibiotic therapy.
The underlying cause of these infections are not always apparent, but are important to consider.
The number of PID patients per million population varies from country to country but a mean value for patients needing immediate treatment has been quoted as 25 per million (European Society for Immunodeficiencies - ESID). There are estimated to be at least twice as many more patients with milder forms of PID who also require treatment. ESID estimated that as many as 70-90% of PID cases worldwide are still undiagnosed, resulting in unnecessary suffering for the patients and increased dependency on healthcare resources for the treatment of lifelong complications and disabilities.