White Blood Cell Disorders

Blood is made up of three different types of blood cells, all of which are produced by the bone marrow:

• Red blood cells, which carry oxygen
• Platelets, which seal wounds and stop bleeding
• White blood cells — leukocytes — which help fight infections

There are several different types of white blood cells, each of which has a specific role in protecting the body from infection:

• Neutrophils, which fight bacteria and fungal infections
• Lymphocytes, which fight viruses, produce antibodies, and regulate the immune system
• Monocytes/macrophages, which are "professional" germ-eating cells
• Eosinophils and basophils, both of which help fight parasites and are related to allergic responses

Many disorders can cause the bone marrow to produce too many or too few white blood cells, or to produce white blood cells that do not function as they should.

Symptoms depend on the type of white blood cell disorder a child has. It's important to obtain an accurate diagnosis from your child's physician. Common symptoms when white blood cells disorders include:

• Frequent infections, most often in the lungs, ears, or sinuses
• Skin abscesses
• Mouth sores
• Invasive fungal infections
• Severe tooth and gum (periodontal) disease

Certain conditions can have unique symptoms, such as delayed wound healing in leukocyte adhesion deficiency and chronic, sometimes greasy, diarrhea in Shwachman-Diamond syndrome

White blood cell disorders occur when the white blood cell count is too low or too high, or when the white blood cells are not functioning properly — conditions of neutrophils and lymphocytes are the most common.

When the white blood cell count is low

Neutropenia is the general term for low numbers of neutrophils in the blood. It may be congenital (due to genetic causes) or acquired (caused by medications/drugs, toxins, viruses, or attacks from the child’s own immune system). Shwachman-Diamond syndrome is a rare inherited disease marked by pancreas dysfunction and congenital neutropenia — low numbers of neutrophils due to insufficient production. Kostmann syndrome is a severe form of congenital neutropenia. In this inherited disorder, the blood virtually lacks neutrophils because they do not mature properly. Patients present with infections and mouth sores early in life.

When the white blood cell count is high

Eosinophilia is a rare increase in the number of eosinophils in the blood, usually as a result of signals produced by other cells calling for more eosinophil production. Neutrophilia, meanwhile, is an increase in the number of neutrophils in the blood. Most commonly, neutrophilia is acquired and occurs in response to infections or drugs. Other rare causes exist.

Depending on the type of white blood cell disorder a child has, the doctor may order:

• Blood work to evaluate white blood cells' number and morphology (appearance)
• Bone marrow testing

Doctors may order additional specific tests to confirm or rule out certain disorders, such as:

• Specific tests for leukocyte function
• Stool sample for Schwachman-Diamond syndrome

After all tests are completed, hematologists will be able to outline the best treatment options.

Treatment depends on the underlying problem (e.g., acquired, congenital) and severity and may include:

• Oral or intravenous antibiotics to fight infection
• Colony-stimulating factor to stimulate the bone marrow to produce more white blood cells

Stem cell (bone marrow) transplant may be an option for severe congenital diseases. Bone marrow transplant involves the replacement of diseased bone marrow with another person’s healthy bone marrow. Unfortunately, it may not be an option for everyone. The success of a transplant depends on many factors, such as how close the match is between child and donor (matched siblings are best; if your child has a sibling, there is a 1-in-4 chance they will be a match) and the patient's age. The decision to proceed with bone marrow transplant should be discussed with your child’s hematologist and a stem cell transplant team.

Thanks to ongoing research, treatment for patients with low white blood cell counts has improved significantly over the past 20 years. Genetic testing, which is now available for many congenital white blood cell disorders, including congenital neutropenias, has allowed better estimation of a patient's prognosis. Improved treatment and supportive care is helping patients with even the most severe of the neutrophil disorders to live longer.

For many children with rare or hard-to-treat conditions, clinical trials provide new options.