What Is Benign Ethnic Neutropenia?

Benign ethnic neutropenia (BEN) is a condition without any symptoms commonly observed in people of African or Middle Eastern descent. It is defined by a persistent low neutrophil count. Neutrophils are the most common type of white blood cell in the body, and they help people fight infection. While neutropenia increases a person's risk for infection (since there are not enough white blood cells to fight infection), people with BEN do not have this increased risk.

This article discusses the causes and diagnostic options for benign ethnic neutropenia.

Defining Benign Ethnic Neutropenia

Neutropenia means a person has a low neutrophil count. BEN is defined by a persistent low neutrophil count of less than 1,000/millimeters³ (mm) to 1,500/mm³, without any cause or symptoms.

Neutropenia is typically inherited or acquired and usually increases a person's risk for infection, though this is not the case for people with BEN.

First described in 1941, approximately 4.5% of African-Americans have the condition, whereas less than 1% of Americans with European ancestry have BEN.

Benign Ethnic Neutropenia Symptoms

People with BEN do not have symptoms.

The diagnosis of BEN should only be made in people who have had repeat testing that shows persistent mild neutropenia, a neutrophil count between 1,000/mm³ to 1,500/mm³, without any symptoms.

People with BEN should not have any of the following:

• Any upper respiratory symptoms suggesting viral infection
• An enlarged spleen or enlarged lymph nodes to suggest lymphoma or leukemia
• Decreased energy or bleeding associated with a low red blood cell count or low platelets
• Be taking medications or have another medical illness that leads to neutropenia
  

Causes

Scientists are not exactly sure why specific populations develop BEN. However, studies show a strong association with a genetic change on the DARC (Duffy antigen receptor for chemokines) gene located on chromosome 1. This genetic change is widespread in Africans and African-Americans and nearly non-existent in white Europeans.

The genetic change in DARC is also protective against Plasmodium vivax, a malaria parasite. Since malaria is widespread in African nations, scientists believe that natural selection contributed to the DARC genetic change being more common in people of African or Middle Eastern descent.

Additionally, since the change in DARC is protective against malaria and is the same change associated with BEN, BEN is more prevalent in people of African and Middle Eastern descent. 

Scientists are still unclear how the genetic change leads to neutropenia. Scientific studies support several different theories, which include:

• Decreased release of neutrophils from the bone marrow, the spongy part of the bone that makes red and white blood cells and platelets
• An alteration of the signals that tell the immune system that it's time to fight infection
• Greater movement of neutrophils into organs like the spleen

However, further exploration is underway because scientists think that other factors must also be involved in the development of BEN.

Diagnosis

BEN is a diagnosis of exclusion, meaning that a healthcare provider should eliminate all other causes of neutropenia first.

People with BEN have a laboratory test that shows a low neutrophil count of less than 1,500/mm³. In addition, they:

• Must not have symptoms of an infection
• Must not have a history or physical exam that suggests another diagnosis
• Must not have other laboratory tests that give another reason for neutropenia

The performed test is called a complete blood cell count, and the white blood cell and absolute neutrophil counts will consistently be a little low in three different samples. Repeat blood tests should be done at least two weeks apart. 

Experts debate about the need for further testing, but there are some general recommendations:

• If a person is not suffering from an infection, does not have other symptoms such as fever, oral ulcers, swollen lymph nodes, or an enlarged spleen, and the neutrophil count is between 1,000/mm³ to 1,500/mm³, then further investigations are not recommended due to the increased expense and stress.
• If a person has symptoms of infection, swollen lymph nodes, or an enlarged spleen, or if the neutrophil count is less than 1,000/mm³, further outpatient investigations to look for another cause of the neutropenia are recommended. 
• If a person has a neutrophil count that is less than 500/mm³, then emergent referral to a hematologist (a doctor who specializes in blood diseases) is recommended.

These guidelines only apply to adults. In children, further testing is required even for mild neutropenia.

Treatment

BEN does not require treatment. It is a benign illness that does not lead to infections or other chronic problems.

However, a chronically low neutrophil count can affect cancer patients who are treated with chemotherapy. People with BEN should discuss with their oncologist or healthcare provider when deciding whether to reduce or stop chemo as a result of a low white blood cell count.

Prognosis

BEN does not increase a person’s risk for further health problems.

With data from the Centers for Disease Control and Prevention (CDC), experts found that people with BEN have: 

• A stable white blood cell and neutrophil counts over several years to decades
• Neutrophil counts that mainly fluctuate in a mild range between 1,000/mm³ to 1500/mm³
• Lower rates of hypertension, diabetes, and musculoskeletal disorders than the average person
• A typical numbers of infections each year
• A low usage of an emergency department or hospital for urgent medical problems

Summary

As the name implies, benign ethnic neutropenia is a mild disorder diagnosed in people of African or Middle Eastern descent that is characterized by low neutrophil counts. The diagnosis does not mean that you are more prone to infection or other health problems. BEN does not require treatment, but it may have implications if you are using chemotherapy for cancer treatment.

A Word From Verywell

If you are of African or Middle Eastern descent and are told that you have a low white blood cell or neutrophil count, you may want to raise the possibility of BEN with your healthcare provider. If you do not have any other symptoms or health problems, you can consider repeat neutrophil count testing rather than other specialized testing and investigations, which can become expensive. Discuss the best diagnostic recommendations with your healthcare provider.