Increased susceptibility of malaria-infected variant erythrocytes to the mononuclear phagocyte system

Abstract

The interactions of the mononuclear phagocyte system with Plasmodium falciparum-infected genetically variant erythrocytes may result in a significant protection for the host. Infected hemoglobin (Hb) EE and Hb EA erythrocytes are more susceptible to phagocytosis by monocytes than are infected Hb AA erythrocytes. The increased susceptibility to phagocytosis of infected erythrocytes was also found for a number of genetic variants involving the α-globin chain, namely, α-thal 1 trait (- -/α α), α-thal 2 trait (- α/α α), Hb H (- -/- α), Hb H/Hb Constant Spring (CS) (- -/α(CS)α), Hb CS trait, and homozygous Hb CS erythrocytes. In addition, oxidative damage from hydrogen peroxide, produced in simulation of macrophages, led to much more effective killing of parasites in glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes than in normal ones. Parasites infecting Hb H/Hb CS also showed an enhanced sensitivity to hydrogen peroxide.