Common Variable Immunodeficiency (CVID)
(See also Overview of Immunodeficiency Disorders.)
Common variable immunodeficiency is an immunodeficiency disorder characterized by very low antibody (immunoglobulin) levels despite a normal number of B cells (lymphocytes).
People with common variable immunodeficiency may have a chronic cough, cough up blood, or have difficulty breathing (due to frequent sinus and lung infections) and may have diarrhea.
To diagnose the disorder, doctors measure immunoglobulin levels and determine how well the body produces immunoglobulins in response to vaccines.
Immune globulin is given throughout life to provide the missing immunoglobulins, and antibiotics are given to treat the frequent infections.
Common variable immunodeficiency is a primary immunodeficiency disorder. It is usually diagnosed between the ages of 20 and 40 but may appear earlier or later in life. The number of B cells is usually normal, but the cells do not mature and thus cannot produce immunoglobulins. In some people with this disorder, T cells (lymphocytes) also malfunction.
The genetic mutations that cause common variable immunodeficiency can be inherited, but more often, they occur spontaneously.
Recurring sinus and lung infections, particularly pneumonia, are common. People may develop a chronic cough, cough up blood, or have difficulty breathing.
Diarrhea may occur, and food may not be absorbed well from the digestive tract. The spleen may enlarge.
Up to 25% of people develop autoimmune disorders. In autoimmune disorders, the immune system attacks the body's own tissue. Examples are autoimmune blood disorders (such as immune thrombocytopenia, autoimmune hemolytic anemia, and pernicious anemia), Addison disease, thyroiditis, and rheumatoid arthritis.
Stomach cancer and lymphoma develop in 10% of people.
Most people have a normal life span, but if another disorder, such as lymphoma or an autoimmune disorder develops and is hard to treat, life span may be shortened.
Doctors suspect common variable immunodeficiency when people have typical symptoms.
Blood tests are done to measure immunoglobulin levels and to determine how well the body produces immunoglobulins in response to vaccines.
If common variable immunodeficiency is diagnosed, doctors do tests yearly to check for disorders that commonly develop in people with this disorder, such as autoimmune disorders, cancers, and lung disorders. Tests may include blood tests, spirometry (lung tests that measure how much air is inhaled and exhaled and how long each breath takes), and imaging (such as computed tomography).
Immune globulin (antibodies obtained from the blood of people with a normal immune system) is given throughout life to provide the missing immunoglobulins. It may be injected into a vein (intravenously) once a month or under the skin (subcutaneously) once a week or once a month.
Antibiotics are promptly given to treat infections.
Autoimmune disorders are treated as needed with drugs that suppress or otherwise modify the immune system's activity (such as rituximab, etanercept, infliximab, or corticosteroids).