title: The Association of High Prevalence of Trophozoites in Peripheral Blood with Lower Antibody Response to P. falciparum Infected Erythrocytes among Asymptomatic Children in Sudan.
abstract: Background. The most prominent variant surface antigens (VSAs) of Plasmodium falciparum are the var gene-encoded Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family, which serves as a parasite-sequestering ligand to endothelial cells. In this study we have examined the antibody reactivity of autologous plasma from symptomatic and asymptomatic malaria infected children against the infected erythrocytes' surface antigens using flow cytometry. Methods. Ethidium-bromide-labelled erythrocytic mature forms of P. falciparum parasites obtained from symptomatic and asymptomatic children were sequentially incubated with autologous plasma and fluorescein isothiocyanate-conjugated (FITC) antihuman IgG. Plasma antibody reactivity was detected by flow cytometry. Results. Asymptomatic children had more prevalence of trophozoites in peripheral blood (66%) compared to symptomatic children (16%), p = 0.002. The mean percentage of infected RBCs reacting with autologous sera was 89.78 among symptomatic children compared to 79.62 among asymptomatic children (p = 0.09). Moreover, the mean fluorescence intensity (MFI) in the asymptomatic was significantly higher compared to symptomatic children (p value = 0.040). Conclusion. Variant surface antigens on Plasmodium falciparum infected RBCs from symptomatic malaria children tend to be better recognized by IgG antibodies. This may suggest a role of some IgG antibodies in severity of malaria.
authors.affiliation: Central Laboratory, Ministry of Higher Education and Scientific Research, Khartoum, Sudan.
authors.forename: Sara N
authors.initials: SN
authors.lastname: Mohamed
authors.affiliation: Central Laboratory, Ministry of Higher Education and Scientific Research, Khartoum, Sudan.
authors.forename: Dina A
authors.initials: DA
authors.lastname: Hassan
authors.affiliation: Central Laboratory, Ministry of Higher Education and Scientific Research, Khartoum, Sudan.
authors.forename: Abdelrahim M
authors.initials: AM
authors.lastname: El Hussein
authors.affiliation: Faculty of Medicine, Al-Zaiem Al Azhari University, Khartoum, Sudan.
authors.forename: Ihssan M
authors.initials: IM
authors.lastname: Osman
authors.affiliation: Institute of Endemic Diseases, University of Khartoum, 11111 Khartoum, Sudan.
authors.forename: Muntasir E
authors.initials: ME
authors.lastname: Ibrahim
authors.affiliation: Institute of Endemic Diseases, University of Khartoum, 11111 Khartoum, Sudan.
authors.forename: Hiba S
authors.identifier: 0000-0003-4227-0212
authors.initials: HS
authors.lastname: Mohamed
authors.affiliation: The Blue Nile Institute for Training and Research, Gezira University, Wad Madani, Sudan.
authors.forename: Bakri Y
authors.initials: BY
authors.lastname: Nour
authors.affiliation: College of Pharmacy, The National Ribat University, Khartoum, Sudan.
authors.forename: Nasreldin H
authors.identifier: 0000-0002-1183-759X
authors.initials: NH
authors.lastname: Abdulhadi
mesh_terms: D000913:Antibodies, Protozoan / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D002648:Child; D004912:Erythrocytes / Q000276:immunology / Q000469:parasitology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016778:Malaria, Falciparum / Q000276:immunology* / Q000378:metabolism / Q000469:parasitology; D008297:Male; D010963:Plasmodium falciparum / Q000276:immunology* / Q000472:pathogenicity*; D015800:Protozoan Proteins; D053058:Trophozoites / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C085731:erythrocyte membrane protein 1, Plasmodium falciparum