Leukopenia: 6 things to know about a low white blood cell count

Leukopenia is the scientific term for having a low white blood cell count. It’s considered a more general term than neutropenia, which is specific to only one type of white blood cell (the neutrophil).  

The Greek prefix “leuko-” means white, while the suffix “-penia”  means “too few.” So, it encompasses all types of white blood cells, including neutrophils, lymphocytes, monocytes, eosinophils and basophils.

Read on to learn why you might have leukopenia, what its symptoms are and how it’s treated.  

What’s the most common reason for a low white blood cell count? 

The causes of leukopenia fall into two main categories. 

1. Your body doesn’t make enough of them. 
2. Some external force, such as an infection, is destroying them. 

Some people’s bodies naturally don’t make white blood cells, like the late David Vetter, who was known as the “Bubble Boy” in the 1970s. But immunodeficiencies like his tend to show up very early.

When older people develop low white blood cell counts, it’s usually because of something else, such as leukemia. Naturally occurring reasons for leukopenia are far less common.

Among our patients at UT MD Anderson, though, cancer treatment — especially chemotherapy — is the most likely reason. Neutropenia is a well-known side effect of chemotherapy.

So, leukopenia doesn’t just mean my body is fighting off an infection?

No. Not unless you’ve been fighting it off for a very long time. 

Are there any other possible causes of leukopenia?

Yes. A genetic variation called benign ethnic neutropenia has been identified in some Black, Middle Eastern and Asian populations who have lower numbers of neutrophils than people of primarily European descent. They aren’t sickly, and they don’t get more infections than anyone else. Their neutrophil counts are just naturally lower than those of others. It’s also sometimes known as Duffy-null associated neutrophil count (DANC).

Much like sickle cells, benign ethnic neutropenia appears to be a natural variation that developed in areas where malaria is prevalent. Sickle cells die more quickly if they’re infected with malaria. But because people with benign ethnic neutropenia also lack a certain receptor on the surface of their red blood cells, malaria can’t even get into them. It gives them natural immunity.  

What are the symptoms of leukopenia?  

Frequent infections, whose symptoms include fever, chills and sweating. That’s why instructions about what to watch out for are some of the most important things we give our patients. That’s also why it’s so important to see your doctor quickly if you develop a fever during cancer treatment. 

When you’re receiving cancer treatments, your body can’t always fight off infection in the same way it normally would. That’s why you may need antivirals or antibiotics.  

How is leukopenia treated? 

Growth factors like filgrastim are available that can stimulate the bone marrow to produce more white blood cells. But we determine whether you need one based on what’s causing it and how often you’re getting sick. Someone who’s getting frequent infections would be treated differently than someone who only gets an occasional cold. 

What’s considered a dangerously low white blood cell count?  

The normal white blood cell range is between 4,000 and 11,000 cells per microliter (mcL). But if you’re not getting sick all the time, even a very low count isn’t necessarily cause for alarm. A “dangerously low” blood count is more about symptoms than numbers. 

Joanne Becker, M.D., is a transfusion specialist in Laboratory Medicine. 

Request an appointment at UT MD Anderson online or call 1-877-632-6789.