Missing IgG Antibody in Babies

The immune system is composed of different types of cells to help the body fight off disease. One type of cells, B lymphocytes, produce antibodies, small proteins that attach to and inactivate invading organisms. Antibodies come in 5 classes (immunoglobulins): G, A, M, E, and D. Immunoglobulin G (IgG) are the antibodies in the body which persist long-term and protect against recurrent infections long after the initial exposure. Children born without IgG face many difficulties with infections without proper treatment.

Immunoglobulin G

• Immunoglobulin G is present in all the body fluids and tissues of the human body. Like the other antibodies, IgG antibodies attach themselves to organisms. This tags the organisms for destruction and/or prevents them from functioning. There are four subclasses of IgG, and a deficiency in any of the subclasses allows opportunistic infections, especially bacterial infections.

Symptoms

• The baby born with an IgG antibody deficiency will appear normal, with no physiological defects noticeable. However, as the child is exposed to viruses and bacteria, the child will develop recurrent infections such as ear infections, pneumonia, upper respiratory infections, sinus infections and throat infections. In people with a normal immune system, exposure to those organisms that cause those infections leads to life-long immunity from another infection.

Diagnosis

• Because there are other immune system problems which may cause similar infections, the health care provider will do a series of laboratory tests to determine what the immune deficiency which is causing those infections. These tests include a complete blood count to count the number of white blood cells. Also, a serum protein electrophoresis will tell the provider if IgG, a protein, is deficient in the child. Other tests, such as genetic tests, are less common, but may be helpful to determine if the IgG deficiency is acquired or inherited, or a combination of both.

Treatment

• Because of the recurrent infections, antibiotics may be prescribed to treat and prevent bacterial infections. Some children with more pronounced IgG antibody deficiencies may be treated with IgG replacement therapy. Depending on the cause of the deficiency, some children may outgrow their need for antibiotics or IgG replacement therapy. So continued consultations with a health care provider are recommended for children with IgG deficiency.

Prognosis

• The prognosis of a baby with missing IgG antibodies depends largely on two factors: the cause of the deficiency and the adherence to treatment. If the cause is reversible or somehow treatable, the child will not require lifelong treatment. If the cause is permanent, the continued use of antibiotics and other therapies will have expected side effects. Nevertheless, the side effects of therapy are preferable compared to the effects of recurrent infections on the lungs and other organs of the child's developing body.