In the absence of Duffy antigens, the malaria parasite (P. vivax) attaches to the red blood cells but cannot invade them.7 21 ACKR1 is thought to affect haematopoiesis, and the lack of ACKR1 on bone marrow erythroid cells induced the development of phenotypically distinct neutrophils that readily leave the circulation to migrate to the spleen.22 The gene discussed is ACKR1; the disease is malaria.