Selective Antibody Deficiency With Normal Immunoglobulins
(See also Overview of Immunodeficiency Disorders.)
Selective antibody deficiency with normal immunoglobulins is characterized by an inadequate response to certain types of antigens (foreign substances in the body) but not to others, even though people have normal or near normal levels of antibodies (immunoglobulins).
People with selective antibody deficiency with normal immunoglobulins have frequent sinus and lung infections.
Doctors diagnose the disorder by measuring immunoglobulin levels in the blood and by evaluating how well people respond to vaccines.
Treatment includes vaccination with the pneumococcal conjugate vaccine, antibiotics to prevent infection, and sometimes immune globulin.
Selective antibody deficiency with normal immunoglobulins is a primary immunodeficiency disorder. It is one of the most common immunodeficiencies that causes frequent sinus and lung infections. People with this disorder have an inadequate immune response to certain vaccines (called polysaccharide vaccines), such as one form of the pneumococcal vaccine.
Vaccines work because they contain antigens from the bacteria or viruses they are to protect against. Normally, the body’s immune system responds to a vaccine by producing substances (such as antibodies) and mobilizing white blood cells that recognize and/or attack the specific bacteria or virus represented in the vaccine. Then whenever people who have been vaccinated are exposed to the specific bacteria or virus, the immune system automatically produces these antibodies and takes other action to prevent or lessen illness. People with selective antibody deficiency do not produce antibodies in response to polysaccharide vaccines.
Affected people have many sinus and lung infections and sometimes symptoms of allergies, such as a chronic runny and stuffy nose (rhinitis), a rash, and asthma. The severity of the disorder varies.
Some children have a form of the disorder that resolves on its own over time.
Children are not tested for this disorder until after age 2 years because young healthy children may have frequent sinus and lung infections and weak responses to certain vaccines.
Testing consists of blood tests to measure levels of immunoglobulins and to evaluate how well the body produces immunoglobulins in response to vaccines. Normal levels of antibodies and an inadequate response to certain vaccines confirms the diagnosis.
As part of their routine childhood vaccinations, children are vaccinated with the pneumococcal conjugate vaccine to prevent pneumococcal infections. Children who have selective antibody deficiency with normal immunoglobulins respond to this vaccine, which differs from the pneumococcal polysaccharide vaccine.
Sinus and lung infections and allergy symptoms are treated. Occasionally, when infections continue to recur after treatment, people are given antibiotics (such as amoxicillin and trimethoprim/sulfamethoxazole) to prevent the infections from recurring.
Rarely, when infections recur frequently despite use of these antibiotics, people are given injections of immune globulin (antibodies obtained from the blood of people with a normal immune system). Immune globulin may be injected into a vein (intravenously) or under the skin (subcutaneously).