FcgammaRIIa (CD32) polymorphism and anti-malarial IgG subclass pattern among Fulani and sympatric ethnic groups living in eastern Sudan.
BACKGROUND
A SNP at position 131, in the FcgammaRIIa gene, affects the binding of the different IgG subclasses and may influence the clinical variation seen in patients with falciparum malaria. This study confirms and extends previous findings, analysing the FcgammaRIIa (CD32) polymorphism in relation to the IgG subclass distribution seen among two sympatric tribes living in eastern Sudan, characterized by marked differences in susceptibility to Plasmodium falciparum malaria.


METHODS
Two hundred and fifty Fulani subjects living in an area of meso-endemic P. falciparum malaria infection were genotyped for the FcgammaRIIa-131 polymorphism. For comparison, 101 non-Fulani donors - (Masaleit, Hausa and Four) - living in the same study area, were genotyped. The levels of plasma antibodies (IgG and subclasses) to four malaria antigens (AMA-1, MSP 2 - 3D7 & FC27, Pf332-C231) were measured using indirect enzyme-linked immunosorbent assays.


RESULTS
The FcgammaRIIa-H/H131 genotype was found to be significantly more prevalent in the Fulani as compared to the non-Fulani ethnic groups (36.0% for Fulani versus 17.8% for non-Fulani, adjusted OR 3.10, 95% CI 1.61-5.97, P value < 0.001). The Fulani showed lower anti-malarial IgG1 and IgG3 antibody levels as compared to the non-Fulani and higher levels of IgG2 antibodies.


CONCLUSIONS
The FcgammaRIIa-H/H131 genotype and H131 allele is at higher frequency in the Fulani ethnic group. The H/H131 genotype was consistently associated with higher levels of anti-malarial IgG2 and IgG3 antibodies, while the R/R131 genotype was associated with higher levels of IgG1 antibodies.
Nasr
Amre
A
Department of Microbiology and Molecular-Biology, Faculty of Science and Technology, Al-Neelain University, Khartoum, Sudan. amre@imun.su.se
Iriemenam
Nnaemeka C
NC
Giha
Hayder A
HA
Balogun
Halima A
HA
Anders
Robin F
RF
Troye-Blomberg
Marita
M
ElGhazali
Gehad
G
Berzins
Klavs
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000818:Animals; D044383:Black People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D016054:DNA, Protozoan / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification* / Q000276:immunology; D016015:Logistic Models; D016778:Malaria, Falciparum / Q000208:ethnology / Q000235:genetics* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D020641:Polymorphism, Single Nucleotide; D017452:Receptors, IgG / Q000235:genetics*; D013397:Sudan
D016054:DNA, Protozoan; C080568:Fc gamma receptor IIA; D007074:Immunoglobulin G; D017452:Receptors, IgG