A to Z: Common Variable Immunodeficiency (CVID)

May also be called: CVID; Common Variable Immune Deficiency; Combined Variable Immune Deficiency; Late Onset Hypogammaglobulinemia

Common variable immunodeficiency (im-yuh-noh-dih-FISH-en-see) is a disorder in which the immune system makes fewer antibodies (special proteins that fight infections) than normal. This puts someone at greater risk of infection and can make infections more severe.

More to Know

The immune system — made up of special cells, proteins, tissues, and organs — defends the body against infections through a process called the immune response. As part of the immune response, special white blood cells (B cells) make proteins called antibodies. Antibodies attach to invaders, such as viruses and bacteria, and mark them for destruction. Common variable immunodeficiency (CVID) causes B cells to produce fewer antibodies, leaving someone less protected against infectious organisms and diseases.

In most cases, doctors don't know what causes CVID, but many believe it has to do with a defect in a gene related to the development and function of B cells. Common infections associated with CVID include pneumonia, sinus infections, ear infections, and infections of the digestive system. Repeated infections eventually can cause lung damage, breathing problems, hearing loss, and ongoing problems in the digestive system.

CVID usually is treated with immunoglobulin replacement therapy. This increases the body's levels of immunoglobulin, the substance in the blood that contains antibodies. Antibiotic medicines also might be given to fight infections resulting from CVID.

Keep in Mind

Immunoglobulin replacement therapy can stop the cycle of repeated infections, but it might have to be given every 2-4 weeks for the rest of someone's life. Quality of life and life expectancy for people with CVID have improved in recent years thanks to better methods of detecting and treating the disorder. The earlier treatment begins, the better the chances of a good outcome.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.