title: Interleukin-21 is associated with IgG1 and IgG3 antibodies to erythrocyte-binding antigen-175 peptide 4 of Plasmodium falciparum in Gabonese children with acute falciparum malaria.
abstract: Interleukin-21 (IL-21) is a newly described, typical, four-helix cytokine showing significant homology with IL-2, IL-4 and IL-15. It regulates IgG1 production and co-operates with IL-4 in the production of multiple antibody classes in vivo. IgG1 and IgG3 are critically involved in the development of clinical immunity to Plasmodium falciparum malaria. However, the mechanisms driving class-switch recombination towards these specific isotypes remain to be elucidated. Seventy-three children with P. falciparum-positive, thick blood smears were recruited from the pediatric wards of the Albert Schweitzer Hospital and the General Hospital in Lambaréné. Children were grouped into two categories according to age: group A (1 to 5 years old) and group B (6 to 16 years old). Patients with severe (severe anemia and/or hyperparasitemia) and mild malaria were enrolled. Prevalence and level of IL-21, total IgG and subclass (IgG1, IgG2, IgG3 and IgG4) titers were determined in plasma by enzyme-linked immunosorbent assay (ELISA). Plasma IL-21 levels correlated with IgG1 and IgG3 levels. Additionally, plasma IL-21 levels correlated with hemoglobin levels in younger children and with parasite density. Here we describe the relationship between IL-21 and antibodies for erythrocyte-binding antigen-175 (EBA-175) peptide 4, a malaria vaccine candidate in Gabonese children with acute falciparum malaria. This study provides new insights into the field of malaria.
authors.affiliation: Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Mewono
authors.forename: Davy W
authors.initials: DW
authors.lastname: Matondo Maya
authors.forename: Pierre-Blaise
authors.initials: PB
authors.lastname: Matsiegui
authors.forename: Selidji T
authors.initials: ST
authors.lastname: Agnandji
authors.forename: Eric
authors.initials: E
authors.lastname: Kendjo
authors.forename: Fortune
authors.initials: F
authors.lastname: Barondi
authors.forename: Saadou
authors.initials: S
authors.lastname: Issifou
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kremsner
authors.forename: Elie
authors.initials: E
authors.lastname: Mavoungou
mesh_terms: D000293:Adolescent; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005681:Gabon; D005786:Gene Expression Regulation; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry*; D007223:Infant; D007378:Interleukins / Q000096:biosynthesis* / Q000502:physiology; D016778:Malaria, Falciparum / Q000097:blood* / Q000276:immunology / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000378:metabolism*; D015800:Protozoan Proteins / Q000737:chemistry*; D000098546:Interleukin-21
chemical_list: D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D007378:Interleukins; D015800:Protozoan Proteins; C065668:erythrocyte-binding antigen 175, Plasmodium; D000098546:Interleukin-21