Plasmodium falciparum glycosylphosphatidylinositol toxin interacts with the membrane of non-parasitized red blood cells:: a putative mechanism contributing to malaria anemia

Following exposure to synthetic Plasmodium falciparum glycosylphosphatidylinositol (P.f.-GPI), red blood cells (RBCs) reacted with antibodies in the serum of a patient with severe acute P. falciparum malaria. Carbohydrate microarray analysis of the patient's serum confirmed the presence of both, IgM and IgG antibodies against P.f.-GPI. The antibodies failed to bind to RBCs when P.f.-GPI lacking the lipid portion was applied. Addition of the detergent Triton X-100 during preincubation with P.f.-GPI resulted in increased recognition. Recognition of P.f.-GPI was dependent on the concentrations of synthetic P.f.-GPI, the serum and the numbers of RBCs. IgM antibodies dominated P.f.-GPI-sensitized RBCs recognition. Recognition by IgM antibodies proved highest during the 1st week of acute malaria and decreased during the following 2 weeks as assessed by flow cytometry and carbohydrate microarray analysis. These results strongly support the notion that released P.f.-GPI can insert into non-parasitized RBC membranes and results in recognition by circulating anti-GPI antibodies and possibly subsequent elimination. This process may contribute to malaria-associated anemia. (C) 2008 Elsevier Masson SAS. All rights reserved.