An Overview of White Blood Cell Disorders

White blood cell disorders occur when you have too many or too few white blood cells. White blood cells, also known as leukocytes, are one of three types of cells that compose the blood. They are produced in the bone marrow and play an important role in your immune system.

Doctors can measure these cells with a test called a white blood cell (WBC) count. When white blood cells are abnormally high, it usually suggests that your immune system is fighting a disease or infection. When they are too low, it suggests that a disease, autoimmune disorder, or other condition has weakened your immune system.

While you cannot diagnose any medical condition based on a white blood cell count, the test can often be the first sign of a disease and even hint at what kind of disease you have.

This article will discuss the different types of white blood cell disorders and how to recognize them. It will also look at the causes, diagnosis, and treatment.

Types

A disorder refers to any condition that disrupts the normal functioning of the body. White blood cell disorders fall into quantitative or qualitative disorders. The first means that normal cells appear in abnormal numbers; the second means the cells themselves have changed.

These disorders manifest in ways that include:

• Leukopenia: A decrease in white blood cells, which can be caused by cells being destroyed or by not enough cells being made
• Leukocytosis: An increase in white blood cells, which can be a normal response of the immune system but also caused by certain cancerous or non-cancerous diseases

There are also five major types of white blood cells, each of which has a specific function:

• Monocytes: Frontline defenders that attack anything the immune system considers abnormal
• Lymphocytes: Blood cells that produce immune proteins called antibodies that target and fight specific disease-causing organisms
• Neutrophils: Blood cells that mainly fight bacterial infections
• Eosinophils: Blood cells that mainly fight parasitic infections
• Basophils: Blood cells that help trigger inflammation to fight infections, diseases, or toxins

Some diseases only affect one type of white blood cell, while others affect many. For instance, lymphocytic leukocytosis only affects lymphocytes, while neutrophilic leukocytosis only affects neutrophils. The type of cells affected can help doctors figure out what type of condition they are dealing with.

Symptoms

Symptoms of white blood cell disorders can vary based on the underlying cause, although some people may be asymptomatic (without symptoms). If symptoms develop, they can often be non-specific. There can even be an overlap in symptoms between leukopenia and leukocytosis.

Causes

There are many different causes of white blood cell disorders. Some are due to a severe infection, an autoimmune disease, genetics, or cancers affecting blood cells or bone marrow.

Others are treatment-related or are caused by problems with other types of blood cells, such as red blood cells. Some are entirely idiopathic, meaning of unknown origin.

Some of the more common reasons for leukopenia include infections (pneumonia among them) or the side effects of certain medications, such as antithyroid drugs. Malnutrition, with low levels of vitamin B12, folic acid, or copper, also can lead to leukopenia.

Some of the white blood cell disorders associated with leukopenia include:

• Aplastic anemia: A bone marrow disorder in which the body stops producing enough new blood cells
• Autoimmune neutropenia: A condition in which your immune system mistakenly attacks and destroys neutrophils
• Congenital neutropenia: A genetic disorder in which the body doesn't make enough neutrophils
• Cyclic neutropenia: A rare genetic disorder in which neutrophil production drops every 21 days or so
• Chronic granulomatous disease: An genetic disorder that causes certain white blood cells to malfunction and behave abnormally
• Leukocyte adhesion deficiencies: A group of rare genetic disorders that affect the white blood cells' ability to fight infection

Leukocytosis also has some common causes, including allergic and drug reactions or bacterial infection. People diagnosed with Epstein-Barr virus (and infectious mononucleosis) also may experience it.

Some of the white blood cell disorders also associated with leukocytosis include:

• Chronic idiopathic neutrophilia: A condition in which neutrophils remain persistently elevated for no apparent reason
  
• Hemolytic anemia: A disorder in which red blood cells die faster than they are made, often due to an underlying genetic or autoimmune cause
• Idiopathic thrombocytopenia: A condition in which your immune system mistakenly attacks and destroys blood-clotting cells called platelets
• Lymphoma: A group of cancers that start in cells of the lymphatic system
• Lymphocytic leukemia: A type of blood cancer that starts in lymphocytes
• Myeloproliferative disorders: Includes six types of slow-growing cancers that cause the overproduction of white blood cells (chronic eosinophilic leukemia, chronic myelogenous leukemia, chronic neutrophilic leukemia, essential thrombocytopenia, polycythemia vera, and primary myelofibrosis)
  

Diagnosis

One of the first tests used to diagnose a white blood cell disorder is a complete blood count (CBC). This test measures all of the different types of blood cells in a sample of blood. It also measures the proportion of individual blood cells, which can help narrow the possible causes.

The lab results are compared to a reference range of high and low values. The reference range for the total white blood cell (WBC) count can vary from one lab to the next but is typically described as follows:

• Males: 5,000 to 10,000 cells per microliter of blood (cells/mL)
• Females: 4,500 to 11,000 cells/mL
  
• Newborns under two weeks of age: 9,000 to 30,000 cells/mL
• Children and adolescents: 5,000 to 10,000 cells/mL

If your results are above or below normal, your doctor will investigate the possible causes. This may include a blood smear in which a drop of blood is placed on a glass slide and examined under the microscope to look for any abnormalities in the cell's structure.

Since white blood cells are produced in the bone marrow, a bone marrow biopsy may also be ordered to get a sample of tissue for evaluation by a pathologist.

If you require further investigation, you may be referred to a hematologist, a doctor who specializes in blood disorders, or an immunologist, a doctor who specializes in disorders of the immune system.

Treatment

The treatment of white blood cell disorders differs according to the cause. Some treatments are used to cure the disease, while others simply manage the disease and keep it in check. Others still are used to relieve symptoms or help normalize the white blood cell count.

Possible treatments include:

• Antibiotics: Used to treat bacterial infections
• Antiparasitic drugs: Used to treat parasitic infections that cause eosinophilia
• Blood component transfusion: This is typically a temporary method to replenish the part of the blood that is lacking until the underlying cause has been handled.
• Colony-stimulating factors (CSF): Medications that increase white blood cell production in the bone marrow
• Glucocorticoids: A medication that may treat the underlying immune disorder and may even move neutrophils from outlying sources back to the peripheral blood.
• Immunosuppressants: Medications that reduce the immune response in people with autoimmune diseases
• Chemotherapy and radiation: Therapies commonly used to treat cancer
• Stem cell transplantation: Used to cure certain blood-related disorders, including myeloproliferative disorders and congenital neutropenia
  

Summary

A white blood cell disorder is one in which the white blood cells are either qualitatively or quantitatively affected. There are many possible causes of this, including infections, genetic disorders, autoimmune diseases, and, in rare cases, cancer. There are even cases in which the cause is unknown.

White blood cell disorders often require extensive tests to uncover the underlying cause. This may include a complete blood count (CBC) and blood smear but also special procedures like a bone marrow biopsy.

The treatment of a white blood cell disorder varies by the cause. While some conditions are serious and require aggressive treatments, such as chemotherapy, others may be relatively minor and require little to no treatment.

A Word From Verywell

There is a wide range of white blood cell disorders, some of which are more serious than others. Many are chronic health concerns, meaning that you have to work closely with your doctor over the long term to keep yourself healthy.

With that said, having an abnormally high or abnormally low white blood cell count doesn't necessarily mean you have a serious disease. Some conditions are readily treatable, while others may have no known cause or symptoms.

If your white blood cell count is abnormal, try not to jump to conclusions. Instead, work with your doctor to reach a diagnosis. If you don't understand what a test result means, ask your doctor to explain so that you can participate fully in any treatment decisions.