Common variable immunodeficiency (CVID) is a primary immune deficiency disease characterized by low levels of protective 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.
NIAID supports research to determine genetic causes of CVID that may lead to therapeutic approaches to address the disease. Researchers also are exploring how antibody-based drugs may lessen the severity of the condition.
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. Only a few of these defects have been identified, and 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 alone is not capable of causing CVID.
CVID is also linked to IgA deficiency, a related condition in which only the level of the antibody immunoglobulin A (IgA) is low, while levels of other antibody types 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.
Symptoms & Diagnosis
People with CVID may 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.
People with CVID also may have diarrhea, problems absorbing food nutrients, reduced liver function, and impaired blood flow to the liver. Autoimmune problems that cause reduced levels of blood cells or platelets also may occur. People with CVID may develop an enlarged spleen and swollen glands or lymph nodes, as well as painful swollen joints in the knee, ankle, elbow, or wrist. In addition, people with CVID may have an increased risk of developing some cancers.
Doctors can diagnose CVID by weighing factors including infection history, digestive symptoms, lab tests showing very low immunoglobulin levels, and low antibody responses to immunization.
CVID is treated with intravenous immunoglobulin infusions or subcutaneous (under the skin) immunoglobulin injection to partially restore immunoglobulin levels. The immunoglobulin given by either method provides antibodies from the blood of healthy donors. The frequent bacterial infections experienced by people with CVID are treated with antibiotics. Other problems caused by CVID may require additional, tailored treatments.
To learn more about CVID, visit the National Library of Medicine, Genetics Home Reference CVID site.