Impact of Duffy-Associated Neutrophil Count on Maintenance Chemotherapy Management in a Child with Acute Lymphoblastic LeukemiaDerek K. Zachman1,2, Jonathan G. Bardahl1, Laurie A. Graves1, and Lars M. Wagner11Division of Pediatric Hematology-Oncology, Duke University Medical Center, Durham NC2Corresponding author:2301 Erwin Road, Durham NC 27710Phone: 919-684-3401, Fax: 919-668-4447dkz3@duke.eduWord Counts: 828Number of Figures/Tables/Supporting Documents: 1 FigureRunning Title: Duffy Associated Neutrophil Count in Pediatric LeukemiaKeywords: pediatric oncology, acute lymphoblastic leukemia, Duffy-associated neutrophil countAbbreviations:

Maintenance therapy is critical for successful treatment of pediatric acute lymphoblastic leukemia (ALL). Chemotherapy dosing during maintenance is guided by the absolute neutrophil count, and may be influenced by the rs2814478 polymorphism causing Duffy-associated neutrophil counts (DANC). Breast cancer patients with DANC experience more neutropenia and reduced treatment intensity, despite not having increased infections. To illustrate the potential impact in pediatric ALL, we describe maintenance therapy for a child with DANC. This case raises the possibility that maintenance therapy may be inappropriately reduced in patients with DANC when using conventional guidelines, potentially contributing to disparities in outcomes.