Available online at www.sciencedirect.com Acta Tropica 105 (2008) 191–195 Short communication Interethnic differences in carriage of haemoglobin AS and Fc receptor IIa (CD32) genotypes in children living in eastern Sudan Amre Nasr a , Gehad ElGhazali b,c , Hayder Giha d , Marita Troye-Blomberg a , Klavs Berzins a,∗ a Department of Immunology, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius v¨ ag 16, SE-10 691 Stockholm, Sweden b Department of Microbiology and Immunology, Faculty of Medicine, University of Khartoum, Sudan c Departmentof Immunology, Faculty of Medicine, King Fahad Medical City, Riyadh, Saudi Arabia d Malaria Research Center (Mal. R. C), Department of Biochemistry, Faculty of Medicine, University of Khartoum, P.O. Box: 102, Khartoum, Sudan Received 28 June 2007; received in revised form 4 October 2007; accepted 5 October 2007 Available online 11 October 2007 Abstract Fulani and Masaleit, two sympatric ethnic groups in eastern Sudan, are characterized by marked differences in susceptibility to Plasmodium falciparum malaria. It has been suggested that sickle cell trait carriage may protect from the most severe forms of malaria. Previously, we have shown that FcRIIa polymorphism is associated with the outcome of malaria disease. The present study aimed at determining whether the two tribes differ in the frequency of FcRIIa and Hb AS genotypes. For this, genotyping of FcRIIa and Hb AS in 70 Fulani and 70 Masaleit age- and sex-matched subjects was conducted. The frequency of FcRIIa H/H131 genotype was higher in the Fulani as compared to the Masaleit group (40.0% versus 14.3%; adjusted odd ratio [OR] = 3.05, 95% confidence interval [CI] = 1.19–7.82 and P = 0.02), while the R/R131 genotype was significantly higher in the Masaleit group (14.3% for Fulani versus 45.0% for Masaleit; adjusted OR = 0.26, 95% CI = 0.11–0.64 and P < 0.01). With regard to FcRIIa allele frequencies, there were significant differences between the Fulani and Masaleit ethnic groups. Thus, the H131 allele was more frequent than the R131 among Fulani children (0.63 versus 0.37, OR = 3.23, 95% CI = 1.93–5.45 and P < 0.001). The frequency of the Hb AS genotype was lower in the Fulani compared to the Masaleit group (15.7% versus 30.0%, respectively, adjusted OR = 0.02, CI = 0.01–0.18 and P < 0.01). These data suggest that FcRIIa and Hb AS polymorphisms may contribute to the clinical outcome of malaria. We conclude that the H/H131 genotype and H131 allele rather than Hb AS genotype (sickle cell trait patients) appear to associate with the Fulani ethnic group. © 2007 Elsevier B.V. All rights reserved. Keywords: Plasmodium falciparum; FcRIIa; Hb AS; Fulani The influence of Plasmodium falciparum parasites on the human genome has been indicated by the distribution of haemoglobin variants. The best-documented example in this context is the sickle cell trait (Hb AS), a genetic abnormality of the human red blood cell due to a mutation in the gene of the beta-chain of globin (S haemoglobin). Its prevalence, known to be 20–25% in Africa (Gendrel et al., 1992), may reach up to 40% in some regions (Bitanga and Rouillon, 1998). It has been suggested that sickle cell trait carriage protects from the most severe forms of malaria, especially in children (Groux and Gysin, 1990; Ringelhann et al., 1976). However, the mechanisms responsible for this protection are still unclear, and appear not solely to be due to the adverse influence of Hb AS erythrocytes on the intra-erythrocytic growth and ∗ Corresponding author. Tel.: +46 8 16 41 70; fax: +46 81 573 56. E-mail address: klavs@imun.su.se (K. Berzins). development of P. falciparum (Bayoumi, 1987). It is possible that the physiological effect of Hb S on parasite growth may trigger an enhancement of the intensity and/or specificity of the host immune response leading to acquisition of protective immunity (Bayoumi, 1987). Indeed, Hb AS, as compared to Hb AA carriers, were shown to have higher levels of antibodies against P. falciparum exoantigens (Marsh et al., 1989) and enhanced lymphocyte in vitro proliferative responses to soluble malaria antigens (Abu-Zeid et al., 1992). However, another study performed in Nigeria demonstrated higher levels of anti- malarial antibodies in HbAA as compared to HB AS carriers (Cornille-Brogger et al., 1979). Early and recent case–control epidemiological studies have demonstrated that persons with the sickle cell trait do become infected with P. falciparum, but that a smaller proportion of those with haemoglobin AS than of those with normal haemoglobin AA develop severe malaria symptoms (Aidoo et al., 2002; Allison, 1954). 0001-706X/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2007.10.003