Absolute neutrophil count by Duffy status among healthy Black and African American adults

Abstract

Many people of African ancestry have lower absolute neutrophil counts (ANC) without increased risk for infection. This is associated with the Duffy null phenotype (non-expression of the Duffy antigen on red blood cells), which is commonly found in those of African descent. Currently, there are no studies that compare the ANC of individuals with Duffy null phenotype to those with Duffy non-null phenotypes within a self-identified Black population. This study aimed to assess the impact of Duffy status on ANC in a healthy population of self-identified Black individuals by adding on a complete blood count with differential as well as a Duffy testing to individuals at a single primary care center. This study found that 66.7% (80/120) of Black individuals have the Duffy null phenotype, and there is a significant difference in ANC between Duffy null and Duffy non-null individuals (Median: 2,820 cells/uL vs 5,005 cells/uL; p<0.001). Additionally, 23.8% (19/80) of Duffy null individuals had an ANC<2,000 cells/uL compared to no Duffy non-null individuals. The Duffy null phenotype is clinically insignificant, but inappropriate reference ranges can propagate systemic racism. Thus, we advocate for development of Duffy null specific ANC reference ranges as well as replacing the term "benign ethnic neutropenia" with Duffy-null associated neutrophil count (DANC).

Prospects for targeting ACKR1 in cancer and other diseases

“…The erythroid silent variant (FyES), though providing malarial protection, loses this developmental cue, resulting in a neutrophil phenotype with altered surface markers and increased propensity to leave circulation ( 64 , 65 ). The observed neutropenia, historically called “benign ethnic neutropenia” and now more accurately “Duffy-associated neutrophil count” (DANC), does not eliminate effective inflammatory immune responses and is hypothesized to be asymptomatic in otherwise-healthy patients ( 66 – 68 ).…”

Development of Duffy Null–Specific Absolute Neutrophil Count Reference Ranges

“…The incidence of type 1 diabetes in children increased during the COVID-19 pandemic, [1][2][3][4] but studies have not discriminated between children with and without infection. We analyzed a large populationbased, individual-patient data set that included diagnoses of COVID-19 to determine whether there was a temporal association between COVID-19 and type 1 diabetes in children.…”

“…This phenotype is reported in 66.7% of individuals identifying as Black in the US and is associated with adequate total body neutrophils with a clinically insignificant lower peripheral neutrophil count . One study found that 23.8% of healthy people with the Duffy null phenotype have an absolute neutrophil count (ANC) below 2000/μL, the lower limit of normal of many reference ranges . With 70% of medical decisions based on laboratory values, reference ranges that do not reflect normal values for a significant proportion of the population may lead to iatrogenic harm.…”

Clinical outcomes of patients referred for asymptomatic neutropenia: A focus on racial disparities in hematology

“…[11][12][13] As such, studies have proposed replacing BEN with more accurate terminology such as Duffy-null associated neutrophil count. 14 Established hematological reference ranges that are historically built on "normal" values among those of European descent disproportionately impact individuals who harbor the Duffy-null phenotype, most of whom are of Black race, leading to inaccurate clinical decision making and excessive diagnostic testing. [15][16][17] Gaining a comprehensive understanding of the demographics and clinical outcomes of patients with asymptomatic neutropenia, as well as variations in institutional references ranges, has the potential to change diagnostic and treatment paradigms.…”

“…The absence of Duffy antigens, as in the Fy(a‐b−) phenotype, prevents malaria merozoites from invading red blood cells (RBC), which explains why people living in geographic areas with high rates of malaria more commonly harbor this phenotype 11–13 . As such, studies have proposed replacing BEN with more accurate terminology such as Duffy‐null associated neutrophil count 14 …”