Common variable immunodeficiency (cvid)

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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.

(See also Overview of Immunodeficiency Disorders.)
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 (antibodies). 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.