Primary Immunodeficiency (PI) : Treatments, Part 5

by National Institute of Health

(Page 9 of 13)

Viruses that are not harmful in children with normal immunity can pose a serious danger. For example, the virus that causes chicken pox (varicella) can trigger a severe infection in the lungs and the brain of SCID patients. Other threats come from the viruses that cause cold sores (herpes simplex) and measles (rubeola).

Laboratory tests confirm multiple problems. There may be extremely low levels of lymphocytes. B cells may be normal in number, but they don't function normally; immunoglobulin levels are low. There are few T cells, and those few are unresponsive. A chest x-ray may show that the thymus gland has failed to develop.

A diagnosis of SCID constitutes a medical emergency. The immediate concern is to bring any current infections under control, and to strengthen the baby's weakened condition with adequate nutrition. IVIG may help to bolster the immune responses.

A lasting remedy, however, requires a more drastic approach. A bone marrow transplant from a matched donor or parent is arranged as quickly as possible.

Children whose SCID is due to ADA Deficiency have another alternative. Injections of PEG-ADA will protect them against recurrent infections, allow them to control ordinary childhood infections such as chicken pox, and make it feasible for them to lead nearly normal lives.

Partial Combined Immunodeficiencies are characterized by both the antibody and cell-based defenses being impaired, but not totally shut down. Problems are limited to certain functions of B cells and certain T cells. In these conditions, the immunodeficiency is part of a complex clinical picture. Other body systems are involved, too. The result is a distinctive set of symptoms, or a syndrome.

Wiskott-Aldrich Syndrome (WAS) is characterized by a tendency to bleed easily and development of an intensely itchy, scaling skin rash (eczema). This is in addition to the severe recurrent infections seen in young boys who develop this X-linked syndrome. Many have brothers or uncles with the same disease.

The infections are the result of abnormal B cells and certain T cell functions. Because of B cell defects, these boys cannot make antibodies against some types of bacteria. This leaves them susceptible to ear infections, pneumonias, blood infections, and meningitis. Because of the T cell defects, they are vulnerable to infections with opportunistic germs, including Candida, Pneumocystis, and the herpes viruses.

Patients with WAS also have defective blood platelets. Platelets are essential for blood clotting as well as certain immune responses. The platelets of youngsters with WAS are too few and too small. (The size of the platelets confirms the diagnosis.)

The lack of platelets causes bleeding, often for no obvious reason. These patients develop bruises, bleeding gums, prolonged nose bleeds, and bloody bowel movements. They also risk deadly bleeding into the brain.

Eczema in WAS can range from mild to severe. It can cause children to itch and scratch themselves until they bleed. This is aggravated by dry skin. Thus, it is important to identify food allergies that cause the skin to itch. Bath oil, moisturizing and steroid creams, and antibiotics on the skin may help relieve the eczema, but keeping the skin clean is also important.

The leading treatment option for WAS is bone marrow transplantation. When marrow is available from a brother or sister who is an identical match, the cure rate exceeds 85 percent.

To correct severe bleeding, a life-saving alternative may be surgery to remove the spleen. In WAS, the spleen wrongly filters platelets out of the blood. Removing the spleen (a relatively simple operation) allows platelets to remain in the bloodstream and prevents dangerous bleeding. However, removing the spleen makes the patient more susceptible to certain infections (e.g., blood poisoning). Consequently, surgery is rarely used. Conservative measures such as antibiotics, IVIG, and avoidance of allergic foods should be tried before spleen removal or BMT.

At one time, a boy with WAS was unlikely to live past the age of 10. Today, thanks to BMT or surgery to remove the spleen coupled with daily antibiotics or regular IVIG to prevent infections, these youngsters may live relatively normal lives for many years. Freed from the risk of easy bleeding and constant infections, they can ride bikes, play contact sports, and mix freely with other children. Many young men with WAS are now living productive lives in their twenties and thirties.

Ataxia-Telangiectasia (AT) is a PI syndrome that affects several body systems, and the symptoms grow worse with time. Children with AT have nervous system problems that cause them to walk unsteadily and clumsily (ataxia), as well as dilated blood vessels (telangiectasia) in the eyes and skin. They also develop frequent sinus and respiratory infections such as bronchitis and pneumonia.

The infections in AT can be traced to defects in both B cells and T cells. B cell responses are substandard, and levels of IgA and IgG may be low. T cells are few and weak; the thymus gland is immature.

Usually AT is first suspected when a child is learning to walk, and has trouble with balance and coordination. A history of infection may or may not be present. The dilated blood vessels typically don't develop before the age of 3 or 4.

The diagnosis can be confirmed by a blood test showing "fetal proteins." These are substances normally produced during the development of a fetus. When levels remain high after birth, it is usually a sign of certain disorders, including AT.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.