label: Duffy Null Polymorphism
label_lc: duffy null polymorphism
description: "A finding indicating that expression of atypical chemokine receptor 1 protein (ACKR1; DARC; Duffy antigen/chemokine receptor) is not detected on a subject's red blood cells. The Duffy null state is associated with leukopenia and neutropenia, decreased rate of HIV disease progression and with resistance to infection by the malarial parasite Plasmodium vivax. (Blood. 2009; 114:2783-2792.)"