Benign ethnic neutropenia is a common, inherited condition in which a person’s circulating neutrophil count sits below the standard laboratory threshold without causing any increased risk of infection. It affects roughly a quarter to half of people of African descent and a smaller but significant share of those with Middle Eastern, West Indian, and certain other ancestries.1PubMed. Benign ethnic neutropenia: what is a normal absolute neutrophil count? Despite the word “neutropenia” in the name, the condition is not a disease, and the people who have it are not immunocompromised. The story of how this normal genetic variation interacts with medical systems built around a single reference range is, in many ways, more consequential than the biology itself.
What Neutropenia Means and Why the Threshold Matters
Neutrophils are white blood cells that serve as the immune system’s first responders against bacterial and fungal infections. In clinical practice, labs flag a result as “neutropenic” when the absolute neutrophil count falls below 1,500 cells per microliter of blood. That cutoff, though, was derived primarily from studies of European-descent populations. There is no strong scientific basis for treating 1,500 as a universal minimum; it is an empirical convention that has been applied across all ethnic groups despite known variation.2PubMed. Benign ethnic neutropenia: what is a normal absolute neutrophil count? Healthy African Americans, for example, have measurably lower white blood cell and neutrophil counts compared to European Americans, and this difference shows up in large population-based reference data.3PubMed. Race-specific WBC and neutrophil count reference intervals
The practical result is that millions of healthy people routinely get flagged with an abnormal lab value. That flag triggers clinical concern, additional testing, and sometimes treatment modifications that are unnecessary. Understanding benign ethnic neutropenia starts with recognizing that the reference range itself is the source of the problem, not the patient’s immune system.
Who Has It and How Common It Is
Benign ethnic neutropenia is one of the most common causes of chronic low neutrophil counts worldwide. It is most prevalent in people of African ancestry, where estimates range from 25 to 50 percent of the population. In Middle Eastern and certain Jewish communities, rates fall to roughly 10 to 15 percent. Among white populations, the condition is rare, affecting less than 1 percent.4Journal of Dermatological Case Reports. Benign ethnic neutropenia: importance of it as India is now center for medical tourism and educational hub People of West Indian descent are also commonly affected.5PubMed Central. Benign ethnic neutropenia
These are not small numbers. In the United States alone, the African American population numbers over 40 million, meaning tens of millions of people carry a neutrophil count that reads as “abnormal” on a standard lab report but reflects their normal baseline. The gap between their healthy biology and what the lab considers normal has real downstream effects in clinical care.
The Genetic Explanation
The primary genetic driver is a variant in the ACKR1 gene, which encodes a protein historically known as the Duffy antigen receptor for chemokines (DARC). A specific regulatory variant, rs2814778, produces what is called the Duffy-null genotype when a person inherits two copies of the C allele. In a large UK Biobank analysis, individuals of Black African or Caribbean ethnicity who were homozygous for this variant (the CC genotype) had a mean neutrophil count of about 2.8 × 10⁹ per liter, compared to 4.4 × 10⁹ per liter in those with at least one T allele.6Human Molecular Genetics. The Duffy-null genotype and risk of infection That is a substantial difference, enough to push many healthy Duffy-null individuals below the conventional 1,500-cell cutoff on a given blood draw.
The Duffy-null genotype is extremely common in sub-Saharan Africa, where it appears at or near 100 percent frequency in some populations. Its prevalence is explained by evolution: the Duffy antigen on red blood cells serves as the entry point for Plasmodium vivax, one of the major malaria parasites. People who lack the receptor cannot be infected by vivax malaria, giving the null allele a powerful survival advantage in malaria-endemic regions. Research in Madagascar, where vivax malaria remains active, has confirmed that natural selection drove the Duffy-null allele to fixation in mainland sub-Saharan African populations.7PubMed Central. Natural selection for the Duffy-null allele in the recently admixed people of Madagascar
Beyond the red blood cell surface, the DARC protein also sits on endothelial cells lining blood vessels, where it acts as a sink for inflammatory signaling molecules called chemokines. The receptor captures chemokines from surrounding tissue, moves them through the cell, and presents them on the blood vessel’s inner surface, helping to direct circulating neutrophils to sites of infection or injury.8PubMed Central. Duffy antigen receptor for chemokines and its involvement in patterning and control of inflammatory chemokines Variants in the DARC gene also regulate circulating levels of key inflammatory mediators like MCP-1, meaning the Duffy system influences the broader balance of inflammation in the body.9Blood. Duffy antigen receptor for chemokines (Darc) polymorphism regulates circulating concentrations of monocyte chemoattractant protein-1 and other inflammatory mediators
Why the Low Count Is Not Dangerous
The word “neutropenia” implies a deficit, but in benign ethnic neutropenia, the body’s total neutrophil supply is not actually reduced. Research suggests that instead of circulating in the blood, more neutrophils in Duffy-null individuals are distributed into tissues, including the spleen. The bloodstream count is lower, but the tissue count compensates. This redistribution likely explains why benign ethnic neutropenia is not associated with increased infection risk: the immune cells are present, just not in the compartment a blood test measures.10PubMed Central. Novel neutrophil biology insights underlying atypical chemokine receptor-1/Duffy antigen receptor of chemokines-associated neutropenia
Long-term follow-up confirms this. In a study tracking adults with benign ethnic neutropenia over time, the low white blood cell counts were stable, infection rates were similar to those of other healthy people seen in the same clinic, and infections that did occur were mild, such as typical upper respiratory infections.11PubMed Central. Natural history of benign ethnic neutropenia in individuals of African ancestry In healthy Black children with neutropenia, a corticosteroid challenge caused the neutrophil count to jump by more than 50 percent in every case, and nearly all exceeded the 2,000-cell mark afterward, demonstrating that the bone marrow has a healthy reserve of neutrophils that can be rapidly mobilized when needed.12PubMed. Leukocyte response to administration of corticosteroid in healthy black children with neutropenia
Unnecessary Bone Marrow Biopsies
One of the most direct harms of misunderstanding benign ethnic neutropenia is the bone marrow biopsy. When a doctor encounters persistently low white blood cell counts without an obvious cause, a biopsy may be ordered to rule out blood cancers or bone marrow failure. A study at a major U.S. medical center examined African American patients with the Duffy-null CC genotype who had been biopsied for isolated low white blood cell counts. Of 34 such patients, 33 had completely normal bone marrow. That is a 97 percent rate of unnecessary invasive procedures.13JAMA Internal Medicine. Association Between a Common, Benign Genotype and Unnecessary Bone Marrow Biopsies Among African American Patients
Bone marrow biopsies are not trivial. They involve inserting a needle into the hip bone, carry a small risk of bleeding and infection, and are painful. When the low count could have been explained by a simple genetic test or a clinical history consistent with lifelong low counts and no infections, the biopsy adds cost and discomfort without diagnostic gain. Awareness of benign ethnic neutropenia among clinicians is the most straightforward way to prevent this.
The Clozapine Problem
Clozapine is widely considered the most effective medication for treatment-resistant schizophrenia. It also carries a rare but serious risk of agranulocytosis, a dangerous drop in neutrophils that can leave a person unable to fight infection. Because of this risk, patients on clozapine must undergo regular blood monitoring, and the drug is stopped if the neutrophil count falls below defined thresholds. Here is where benign ethnic neutropenia collides with drug safety rules: patients whose baseline counts are already low may be denied clozapine entirely or have it discontinued unnecessarily.
In a genome-wide study of individuals of African ancestry on clozapine, those homozygous for the Duffy-null variant were over 20 times more likely to have their clozapine stopped for neutropenia than those without the variant.14Molecular Psychiatry. A genome-wide association study in individuals of African ancestry reveals the importance of the Duffy-null genotype in the assessment of clozapine-related neutropenia These interruptions were driven by the genetically lower baseline, not by clozapine-induced immune toxicity. For patients with severe psychotic illness, losing access to the one medication that controls their symptoms can be devastating.
Evidence supports adjusted monitoring. A systematic review found that people with benign ethnic neutropenia show no signs of impaired immune function, and their infection rates are comparable to those of the general population. The review concluded that a neutrophil count above 1,000 cells per microliter is a safe threshold for starting or resuming clozapine in these patients, lower than the 1,500-cell standard.15The Journal of Clinical Psychiatry. Benign Ethnic Neutropenia and Clozapine Use: A Systematic Review of the Evidence and Treatment Recommendations A more recent multi-ethnic study from the United Arab Emirates echoed this, finding that low neutrophil counts during clozapine treatment were uncommon and strongly tied to baseline levels and benign ethnic neutropenia status, suggesting that baseline-informed monitoring can reduce unnecessary treatment interruptions.16Schizophrenia Research. Baseline neutrophil count, benign ethnic neutropenia risk, and clozapine haematological monitoring: A multi-ethnic retrospective cohort study from the United Arab Emirates In cases where clozapine is especially critical and the neutrophil count keeps dipping, granulocyte colony-stimulating factor (G-CSF) can be used to temporarily boost the count, though the response can be variable and requires close monitoring.17PubMed. Granulocyte colony stimulating factor (G-CSF) can allow treatment with clozapine in a patient with severe benign ethnic neutropaenia (BEN): a case report
Chemotherapy Delays and Dose Reductions in Cancer Treatment
The same misapplied threshold creates problems in oncology. Most chemotherapy protocols hold treatment or reduce the dose when the neutrophil count drops below a set level, because chemotherapy itself suppresses the bone marrow. For patients with benign ethnic neutropenia, their pre-treatment baseline is already near or below those thresholds, which means the standard rules trigger delays and reductions that are not medically necessary.
A study at Columbia-Presbyterian Medical Center compared African American and white women undergoing adjuvant chemotherapy for early-stage breast cancer. The African American women had significantly lower white blood cell counts at diagnosis (about 6.2 vs. 7.4 × 10⁹ per liter) and required a significantly longer treatment duration as a result, 19 weeks versus 15 weeks. That four-week difference translated directly into lower dose intensity, meaning the African American women received less chemotherapy per unit of time. The researchers raised the possibility that this disparity contributes to observed racial differences in breast cancer survival.18PubMed. Ethnic neutropenia and treatment delay in African American women undergoing chemotherapy for early-stage breast cancer
Newer targeted cancer drugs face the same issue. Palbociclib, widely used for advanced breast cancer, commonly causes neutropenia as a side effect. A study examining patients with the Duffy-null variant found that they experienced much higher rates of severe neutropenia on palbociclib (about 72 percent versus 23 percent in patients with the standard genotype), required dose reductions far more often, and ultimately had a lower average dose intensity and a lower clinical benefit rate.19PubMed Central. Hematologic safety of palbociclib in combination with endocrine therapy in patients with benign ethnic neutropenia and advanced breast cancer Whether this reflects genuine drug toxicity or simply a lower starting count being pushed further below the cutoff is exactly the kind of question that adjusted reference ranges could help answer.
Exclusion From Clinical Trials
The ripple effects extend to research enrollment. Many clinical trials require participants to have a minimum neutrophil count at screening. A review of prostate cancer trials found that over 40 percent excluded patients with benign ethnic neutropenia, a condition that almost exclusively affects Black men. The neutrophil count threshold alone could exclude 6 to 8 percent of Black patients who have perfectly healthy immune systems.20The American Journal of Managed Care. Eligibility Requirements Exclude Black Patients From Prostate Cancer Clinical Trials This exclusion feeds a cycle: trial populations skew white, trial results inform treatment guidelines that may not account for the populations that were underrepresented, and health disparities persist.
Benign Ethnic Neutropenia in Children
The condition is present from birth, which means pediatricians encounter it regularly. Children of African descent and other affected groups often show persistently low neutrophil counts during routine blood work or evaluations for common childhood illnesses. A study characterizing children with benign ethnic neutropenia found that counts were similarly low across age groups and ethnic backgrounds within the condition. Young children under six had the lowest absolute neutrophil counts of any age group, which can be especially alarming to parents and providers unfamiliar with the condition.21PubMed Central. Identification and Clinical Characterization of Children with Benign Ethnic Neutropenia
For families, the key reassurance is that these children are not at increased risk of infection. The low count does not worsen over time, does not evolve into a blood disorder, and does not require treatment. The main risk in pediatrics is the same as in adults: unnecessary workups, referrals, and parental anxiety triggered by a lab value that was never designed to account for their child’s genetics.
Stem Cell and Blood Donation
Given that benign ethnic neutropenia reflects a redistribution of neutrophils rather than a true shortage, you might wonder how these individuals respond when the bone marrow is pushed to mobilize cells. The answer is surprisingly robust. When African American donors with benign ethnic neutropenia received G-CSF (the standard drug used to mobilize stem cells for donation), their neutrophil counts increased by an average of 23-fold, compared to a 13-fold increase in African American donors with normal baseline counts.22PubMed Central. Hematopoietic Progenitor Cell Mobilization is More Robust in Healthy African American Compared to Caucasian Donors and is not Affected by the Presence of Sickle Cell Trait A separate study found that while African American donors started with lower baseline counts, their G-CSF-stimulated neutrophil rise was significantly greater than that of matched Caucasian donors, and the final product cell counts were comparable.23PubMed. African American adult apheresis donors respond to granulocyte-colony-stimulating factor with neutrophil and progenitor cell yields comparable to those of Caucasian and Hispanic donors
This has practical significance for the transplant field. Bone marrow and stem cell registries need donors who are genetically similar to recipients, and the need for African American and other minority donors far outstrips supply. If benign ethnic neutropenia were used as a reason to defer potential donors, it would further shrink an already-limited pool. The evidence says it should not.
The Naming Debate
The term “benign ethnic neutropenia” is itself under scrutiny. Critics argue that “ethnic” implies race is a biological category rather than a social one, and that the label reinforces the idea that certain racial groups are biologically deviant from a white-derived norm. A narrative review in Schizophrenia Research concluded that the diagnosis has limited construct validity in the U.S. context, reinforces false notions of biological race, and should be renamed using language like “familial” or “hereditary” neutropenia instead. The authors also called for a global expansion of neutrophil count reference ranges in monitoring guidelines rather than maintaining a single standard with a race-based exception bolted on.24PubMed. Re-examining the utility and validity of benign ethnic neutropenia: A narrative literature review
Others in hematology have pushed for eliminating race-based reference ranges altogether, arguing that the practice creates separate standards of “normal” based on ancestry, which complicates clinical decision-making and embeds structural bias into laboratory medicine.25The Lancet Haematology. Eliminating race-based reference ranges in haematology: a call to action The tension is real: race-specific ranges can help clinicians avoid unnecessary interventions in the short term, but they also formalize a framework in which white physiology is treated as the default and everyone else gets an asterisk. The underlying genetics are clear, the Duffy-null variant drives the phenotype, and a genotype-informed approach rather than a race-informed one would sidestep much of this debate.
When Low Counts Are Not Benign
One important caution: a low neutrophil count in a person of African or Middle Eastern descent is not automatically benign ethnic neutropenia. Other causes of persistent neutropenia exist. Autoimmune diseases like lupus frequently cause low neutrophil counts, and lupus disproportionately affects Black women. Drug side effects, viral infections, nutritional deficiencies, and bone marrow disorders can all lower the count independently. The Duffy-null genotype provides a plausible explanation only for mild, stable neutropenia in an otherwise healthy person with no symptoms of immune compromise.
Clinicians evaluating a patient with low counts should consider the clinical picture as a whole. A history of lifelong low counts discovered incidentally, no increased infections, and ancestry consistent with Duffy-null prevalence all point toward the benign condition. New-onset neutropenia, counts below 500, accompanying symptoms, or counts that are dropping over time all warrant further workup regardless of the patient’s background. Benign ethnic neutropenia is a diagnosis of exclusion and of pattern recognition, not a blanket label to dismiss low counts in any person who happens to be Black.