Research
FcγRIIa (CD32) polymorphism and anti-malarial IgG subclass pattern among Fulani and sympatric ethnic groups living in eastern Sudan
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* Corresponding author: Amre Nasr amre@imun.su.se
1 Department of Microbiology and Molecular-Biology, Faculty of Science and Technology and Al-Neelain Research Centre, Faculty of Medicine, Al-Neelain University, PO Box 12702, Khartoum, Sudan
2 Department of Immunology, Wenner-Gren Institute, Stockholm University, SE 10691 Stockholm, Svante Arrhenius väg 16, SE-10 691 Stockholm, Sweden
3 Department of Medical Microbiology and Parasitology, College of Medicine of the University of Lagos, Idi-araba, PMB 12003 Lagos, Nigeria
4 Department of Biochemistry, Faculty of Medicine, University of Khartoum, PO Box 102 Khartoum, Sudan
5 Department of Medical Biochemistry, Faculty of Medicine and Medical Sciences, Arabian Gulf University, PO Box 26671 Manama, Bahrain
6 Department of Biochemistry, La Trobe University, Victoria 3086, Australia
7 Department of Clinical Immunology, Pathology and Clinical Laboratory Medicine, Faculty of Medicine, King Fahad Medical City, Riyadh, Saudi Arabia
Malaria Journal 2009, 8:43 doi:10.1186/1475-2875-8-43
Published: 13 March 2009Abstract
Background
A SNP at position 131, in the FcγRIIa 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 FcγRIIa (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 FcγRIIa-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 FcγRIIa-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.
Conclusion
The FcγRIIa-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.