Marked differences in CRP genotype frequencies between the Fulani and sympatric ethnic groups in Africa.
BACKGROUND
C-reactive protein (CRP) is an acute phase protein that can activate various immune cells and bind to certain Fcgamma 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.


CONCLUSIONS
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.
Israelsson
Elisabeth
E
Department of Cardiology, Karolinska University Hospital Solna, 17176 Stockholm, Sweden. per.tornvall@karolinska.se.
Ekström
Mattias
M
Nasr
Amre
A
Dolo
Amagana
A
Kearsley
Susannah
S
Arambepola
Gishanthi
G
Homann
Manijeh Vafa
MV
Maiga
Bakary
B
Doumbo
Ogobara K
OK
Elghazali
Gehad
G
Giha
Hayder A
HA
Troye-Blomberg
Marita
M
Berzins
Klavs
K
Tornvall
Per
P
D000293:Adolescent; D000328:Adult; D000483:Alleles; D002097:C-Reactive Protein / Q000235:genetics* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000208:ethnology* / Q000235:genetics / Q000276:immunology; D008297:Male; D008302:Mali / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000235:genetics / Q000302:isolation & purification*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011157:Population Dynamics; D013397:Sudan / Q000453:epidemiology; D055815:Young Adult
D002097:C-Reactive Protein