Common variable immunodeficiency (CVID) is characterized by low levels of antibodies and an increased risk of infections. Although the disease usually is diagnosed in adults, it also can occur in children. CVID also is known as hypogammaglobulinemia, adult-onset agammaglobulinemia, late-onset hypogammaglobulinemia, and acquired agammaglobulinemia.
Causes
CVID is caused by a variety of different genetic abnormalities that result in a defect in the capability of immune cells to produce normal amounts of all types of antibodies, also called immunoglobulins. Only a few of these defects have been identified, and therefore the cause of most cases of CVID is unknown. Many people with CVID carry a DNA variation called a polymorphism in a gene known as TACI. However, while this genetic abnormality confers increased risk of developing CVID, it is not capable of causing CVID alone.
IgA deficiency is a related condition in which only the level of the antibody immunoglobulin A (IgA) is definitely low, while levels of other immunoglobulin types such as IgG and IgM are usually normal or near normal. IgA deficiency typically occurs alone, but in some cases it may precede the development of CVID or occur in family members of CVID patients.
Signs and Symptoms
People with CVID can experience frequent bacterial and viral infections of the upper airway, sinuses, and lungs. Acute lung infections can cause pneumonia, and long-term lung infections may cause a chronic form of bronchitis known as bronchiectasis, which is characterized by thickened airway walls colonized by bacteria.
Respiratory infection may be associated with
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- Diarrhea and problems absorbing food nutrients
- Reduced liver function and impaired blood flow to the liver
- Painful swollen joints in the knee, ankle, elbow, or wrist
- Enlarged spleen and swollen glands or lymph nodes
- Autoimmune problems that cause reduced levels of blood cells or platelets
- Increased risk of developing some cancers
Diagnosis
Doctors can diagnose CVID by weighing several factors:
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- History of recurrent infections, especially of the lungs
- Occurrence of digestive system problems
- Lab tests showing very low immunoglobulin levels
- Low antibody responses to immunization
For more information on CVID research and patient care please visit the NIAID PIDD site
You can also download the booklet from IPOPI on CVID