Leukocyte Adhesion Deficiency

LAD is a rare PI disease, found in one out of every million people. This disease causes recurrent, life-threatening infections. Phagocytes cannot find their way to the site of infection to fight off invading germs. LAD is autosomal recessive disease, meaning that to be born with this disease, both parents must have the affected gene.

What causes LAD?

LAD is caused by a lack of beta 2 integrin, also called CD18, molecules. These molecules are normally found on the outer surface of phagocytes. Without them, the phagocytes cannot attach to blood vessel walls and enter infected tissues where they help fight infection. Mutations in the gene that instructs, or codes for, the production of CD18 cause LAD.

What are the symptoms of LAD?

Children with LAD cannot fight off infection properly. They may have

• Severe infections of the soft tissue
• Eroding skin sores without pus
• Severe infections of the gums with tooth loss
• Infections of the gastrointestinal tract
• Wounds that heal slowly and may leave scars

There are at least two forms of LAD

• A severe form, called LAD type 1, which commonly causes death in early infancy from infections
• A more moderate form in which children may survive into young adulthood

How is LAD diagnosed?

Blood tests to diagnose patients with LAD show a very high number of white blood cells and very low levels of CD18, a protein. Doctors may suspect LAD if an infant's umbilical cord does not fall off and heal properly after birth. They also will suspect the disease in children who develop severe infections caused by bacteria and fungi, and whose wounds are slow to heal.

How is LAD treated?

Doctors treat patients with bacterial infections early and aggressively with antibiotics. Some patients have been treated successfully with bone marrow transplants.

Interferon gamma increases CD18 and improves the ability of white blood cells to move about. NIAID researchers are using interferon gamma in people with LAD type 1 to see if it can help reduce the number and severity of their recurrent infections. Researchers are also investigating gene therapy as a potential cure for LAD.

For More Information:

• Primary Immunodeficiency

^{reproduced from the National Institute of Allergy and Infectious Diseases Fact Sheet on Primary Immune Deficiency}