Cytoadherence and genotype of Plasmodium falciparum strains from symptomatic children in Franceville, southeastern Gabon.
BACKGROUND
Plasmodium falciparum causes severe clinical manifestations by sequestering parasitized red blood cells (PRBC) in the microvasculature of major organs such as the brain. This sequestration results from PRBC adherence to vascular endothelial cells via erythrocyte membrane protein 1, a variant parasite surface antigen.


OBJECTIVE
To determine whether P. falciparum multiple genotype infection (MGI) is associated with stronger PRBC cytoadherence and greater clinical severity.


METHODS
Nested polymerase chain reaction was used to genotype P. falciparum isolates from symptomatic children and to distinguish between single genotype infection (SGI) and MGI. PRBC cytoadhesion was studied with cultured human lung endothelial cells.


RESULTS
Analysis of two highly polymorphic regions of the merozoite surface antigen (MSP)-1 and MSP-2 genes and a dimorphic region of the erythrocyte binding antigen-175 gene showed that 21.4% and 78.6% of the 42 children had SGI and MGI, respectively. It also showed that 37 (89%) of the 42 PRBC samples expressed MSP-1 allelic family K1. Cytoadherence values ranged from 58 to 1811 PRBC/mm(2) of human lung endothelial cells monolayer in SGI and from 5 to 5744 PRBC/mm(2) in MGI. MGI was not associated with higher cytoadherence values or with more severe malaria.


CONCLUSIONS
These results suggested that infection of the same individual by multiple clones of P. falciparum does not significantly influence PRBC cytoadherence or disease severity and confirmed the predominance of the MSP-1 K1 genotype in southeastern Gabon.
Touré
Fousseyni S
FS
Centre International de Recherches, Médicales de Franceville, BP 769 Franceville, Gabon. fousseyni@yahoo.fr
Ouwe-Missi-Oukem-Boyer
Odile
O
Mezui-Me-Ndong
Jérôme
J
Ndong-Atome
Guy Roger
GR
Bisvigou
Ulrick
U
Mazier
Dominique
D
Bisser
Sylvie
S
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016054:DNA, Protozoan / Q000097:blood; D004912:Erythrocytes / Q000469:parasitology*; D005681:Gabon; D005838:Genotype; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000472:pathogenicity*; D016133:Polymerase Chain Reaction; D020545:Respiratory Mucosa / Q000166:cytology; D012720:Severity of Illness Index; D014774:Virulence
D016054:DNA, Protozoan