PF4 and malaria: Platelet-mediated parasite killing encompasses PF4, a CXC-type chemokine secreted by activated platelets from intracellular a granules, that, on crossing through membrane to permeate into erythrocytes via Duffy antigen (Fy), a receptor for chemokine and malaria parasites expressed by erythrocyte, kills Plasmodium species by inducing selective cytolysis of the parasite digestive vacuole.