Research

Marked differences in CRP genotype frequencies between the Fulani and sympatric ethnic groups in Africa

Elisabeth Israelsson¹ , Mattias Ekström² , Amre Nasr¹ , Amagana Dolo³ , Susannah Kearsley¹ , Gishanthi Arambepola¹ , Manijeh Vafa Homann¹ , Bakary Maiga³ , Ogobara K Doumbo³ , Gehad ElGhazali^4,5 , Hayder A Giha^6,7 , Marita Troye-Blomberg¹ , Klavs Berzins¹ and Per Tornvall²

¹  Department of Immunology, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden

²  Department of Cardiology, Karolinska University Hospital Solna, 17176 Stockholm, Sweden

³  Malaria Research and Training Center (MRTC), Faculty of Medicine and Pharmacy, University of Bamako, Bamako, Mali

⁴  Department of Immunology, Faculty of Medicine, King Fahad Medical City, Riyadh, Saudi Arabia

⁵  Department of Microbiology and Immunology, Faculty of Medicine, University of Khartoum, Sudan

⁶  Malaria Research Center, Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan

⁷  Department of Medical Biochemistry, College of Medicine and Health Sciences, Arabian Gulf University, Manama, Bahrain

author email corresponding author email

Malaria Journal 2009, 8:136doi:10.1186/1475-2875-8-136

Published:	22 June 2009

Abstract

Background

C-reactive protein (CRP) is an acute phase protein that can activate various immune cells and bind to certain Fcγ receptors. The latter may compete with the binding of IgG antibodies to these receptors and could thereby interfere with the antigen-specific immune response. Polymorphisms in the promoter region of the CRP gene have been strongly associated with the plasma concentration of CRP. The known lower susceptibility to malaria in the Fulani ethnic group, as compared to their sympatric neighbours in Africa, has been linked to different genetic backgrounds. The present study was performed to investigate if polymorphisms in the CRP gene could contribute to the lower susceptibility to malaria seen in the Fulani ethnic group.

Methods

The CRP -717 T>C, -286 C>T>A, and +1444 C>T polymorphisms were analysed in asymptomatic Fulani and non-Fulani individuals from Mali and Sudan using Pyrosequencing T and TaqMan r MGB probes.

Results

The rare -286 A allele, previously shown to be associated with increased CRP expression and plasma levels, was shown to be more frequent in the non-Fulani ethnic groups as compared to the sympatric Fulani ethnic group both in Mali and Sudan. The common -717 T allele was more prevalent in the non-Fulani ethnic group compared to the sympatric Fulani ethnic group, but only in Mali. The parasite prevalence was increased for the -286 A allele, but not for the -717 T allele. No differences regarding genotype frequency or parasite prevalence were seen for +1444 C>T.

Conclusion

This study indicate that CRP may play an important role in the immune responses to malaria, and that the -286 C/T/A CRP polymorphism may be a contributing factor to the lower susceptibility to malaria seen in the Fulani.