White Blood Cell Disorders

What white blood cells do

White blood cells (leukocytes) are made in the bone marrow and travel in the blood and lymph system. A normal adult count is roughly 4,000 to 11,000 cells per microliter of blood, although labs use slightly different ranges. There are five main types:

Types of white blood cell disorders

High white blood cell count (leukocytosis)

A high count is most often the body's normal response to infection, inflammation, injury, smoking, pregnancy or medicines such as steroids. It usually returns to normal once the trigger passes. Very high counts, or immature cells (blasts) on a blood smear, suggest a bone marrow disease such as leukemia or a myeloproliferative neoplasm.

People searching for an "extra white blood cells disease" are usually asking about leukemia. In leukemia, the marrow produces large numbers of abnormal white cells that do not fight infection and crowd out normal blood production. That is why leukemia causes infections, anemia and bleeding even though the white count may be high.

Low white blood cell count (leukopenia)

The commonest kind is neutropenia. Causes include chemotherapy, viral infections, some antibiotics, antithyroid and antipsychotic medicines, autoimmune disease such as lupus, vitamin B12 or folate deficiency, an enlarged spleen, and bone marrow failure such as aplastic anemia. Some people of African or Middle Eastern ancestry have a naturally lower neutrophil count (Duffy-null associated neutrophil count) without extra infection risk.

Blood and lymph cancers

• Leukemias: acute and chronic, myeloid and lymphoid.
• Lymphoma: cancers of lymphocytes, mainly in lymph nodes, causing painless swelling, fevers, night sweats and weight loss.
• Multiple myeloma: a cancer of plasma cells, the antibody-making cells, causing bone pain, anemia and kidney problems.
• Myelodysplastic syndromes: faulty marrow that makes too few healthy cells.

Disorders of white cell function

Here the count may be normal but the cells do not work. Examples are chronic granulomatous disease, leukocyte adhesion deficiency and other primary immunodeficiencies, which are usually inherited and appear in childhood with severe or unusual infections. Acquired causes include HIV and immune-suppressing medicines.

Abnormal distribution of white cells

White cells can be counted as low in the blood when they are actually pooled elsewhere, for example trapped in an enlarged spleen, or stuck to vessel walls. They can also gather in tissues abnormally, as with eosinophils in eosinophilic esophagitis or in hypereosinophilic syndrome. Doctors look at where the cells are, not only how many there are.

Symptoms

Many white cell disorders cause no symptoms and are found on a routine blood test. When symptoms appear they include:

• frequent infections, or infections that are severe or caused by unusual germs
• fever, chills and night sweats
• tiredness and weakness
• mouth ulcers and gum infections
• swollen lymph nodes, enlarged spleen or liver
• unexplained weight loss
• easy bruising and bleeding, if the marrow problem also lowers platelets

How they are diagnosed

1. Complete blood count (CBC) with differential: measures the total white count and each type.
2. Repeat testing: many mild abnormalities resolve on a test a few weeks later.
3. Peripheral blood smear: a specialist looks at the cells under a microscope for abnormal shapes or immature cells.
4. Further blood tests: for infection, vitamin levels, autoimmune markers, HIV and flow cytometry, which identifies abnormal cell populations.
5. Bone marrow biopsy: a sample from the hip bone shows how blood cells are being made. It is used when leukemia, myelodysplasia or marrow failure is suspected.
6. Imaging: CT or PET scans for lymphoma.

Treatment

Treatment is aimed at the cause:

• Treating the infection or stopping the medicine responsible.
• Growth factors (G-CSF) to raise neutrophil counts during chemotherapy.
• Antibiotics or antifungals to prevent or treat infection.
• Chemotherapy, targeted therapy, immunotherapy and radiotherapy for blood cancers.
• Stem cell (bone marrow) transplant for some leukemias, marrow failure and inherited immune disorders.
• Immunoglobulin replacement for some antibody deficiencies.

Living with a low white count

If your neutrophils are low, wash your hands often, avoid people with infections, keep vaccines up to date as advised (avoiding live vaccines when told), handle and cook food safely, and take your temperature if you feel unwell. A fever needs same-day medical attention.

Frequently asked questions

What disease causes extra white blood cells?

The most common reason for a high count is infection, which is temporary. Diseases that cause persistently high counts include leukemia, other bone marrow cancers called myeloproliferative neoplasms, chronic inflammatory diseases, and smoking. A blood smear and further tests separate a reaction from a disease.

Is there a disease related to bad distribution of white blood cells?

Yes. An enlarged spleen can trap white cells, lowering the blood count. In hypereosinophilic syndrome and related disorders, eosinophils build up in tissues such as the heart, lungs and gut. In leukemia, abnormal cells may also infiltrate the gums, skin or nervous system.

What is a dangerously low white blood cell count?

Doctors focus on neutrophils. A neutrophil count below 1,500 per microliter is neutropenia, and below 500 is severe, with a high risk of serious infection. Anyone with severe neutropenia who develops a fever needs emergency treatment.

Can stress cause a high white blood cell count?

Yes. Physical stress such as surgery, injury, intense exercise or a seizure, and severe emotional stress, can raise the count temporarily through stress hormones. Steroid medicines have the same effect. The count normally settles within hours to days.

Are white blood cell disorders always cancer?

No. Most abnormal white counts are caused by infections, medicines or inflammation and resolve on their own. Blood cancers are one group of white cell disorders, but many others are benign or treatable. A doctor will interpret the result alongside your symptoms and repeat tests.