573 - Duffy Negative Phenotype and Elevated Absolute Neutrophil Count in Pediatric Sickle Cell Population

Poster Number: 573
Publication Number: 573.321

Kokila Jeyamurugan, Brookdale Hospital Medical Center, Brooklyn, NY, United States; Min-Kyung Jung, New York Institute of Technology College of Osteopathic Medicine, Oakland Gardens, NY, United States; Kusum Viswanathan, One Brooklyn Health, Brooklyn, NY, United States; Fernanda E. Kupferman, One Brookdale Health at Brookdale Hospital Medical Center, Brooklyn, NY, United States; Mario Peichev, BHMC, Brooklyn, NY, United States

Background: Benign Ethnic Neutropenia (BEN) has long been observed in people of African descent. The Duffy negative trait is considered to be the major genetic determinant of BEN. While many African American children with sickle cell disease (SCD) are found to be Duffy antigen negative, they are shown to have elevated white blood counts (WBC). This may be due to the fact that SCD is associated with a pro-inflammatory state, which accounts for the elevated baseline leukocyte count and inflammatory cytokines in this subset of population. Little is known about the impact of Duffy negativity in pediatric population.

Objective: To assess the variation in absolute neutrophil count among Duffy negative children with and without sickle cell disease

Design/Methods: This is a retrospective cohort study that included patients with and without SCD ≤ 18 years of age with Duffy negative trait followed in hematology clinic from January 2019 to June 2021; Steady state data for patients with SCD were obtained during their routine clinic visit. Control group included asymptomatic patients referred for evaluation of persistent neutropenia. Children with immunodeficiency, any infection, recent steroid use and SCD patients on hyper transfusion were excluded. Outcome variables included absolute neutrophil count (ANC), WBC, hemoglobin, platelet count and C-reactive protein (CRP). To test the differences between Duffy negative patients with SCD vs. without SCD, Mann-Whitney U test was used for continuous outcome, and chi-square test for categorical outcome variables.

Results: A total of 62 children were included in the analysis. The median age was 12 years; 69.4% of patients were male; 80.6% were African Americans. The ANC, WBC, platelet count and CRP all showed a significant increase in Duffy negative children with SCD. A considerable drop in hemoglobin was noted in the SCD group. The use of hydroxyurea had no statistically significant effect on the outcome variables in the SCD group.Conclusion(s): Duffy negative children with SCD can have an elevated WBC and ANC compared to Duffy negative children without SCD. The persistent inflammatory state in SCD help to overcome the impact of Duffy negativity on WBC/ ANC, even when challenged with hydroxyurea. An overreacted and stimulated bone marrow secondary to chronic anemia due to hemolysis could be another possible explanation.
kj resume recent.pdf
Comparison of outcome variable across different type of SCD and Hydroxyurea use