Identification of complement receptor one (CR1) polymorphisms in west Africa

• Published in: Genes and immunity Vol. 1; no. 5; pp. 325 - 329
• Main Authors: Moulds, J M, Kassambara, L, Middleton, J J, Baby, M, Sagara, I, Guindo, A, Coulibaly, S, Yalcouye, D, Diallo, D A, Miller, L, Doumbo, O
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.06.2000
• Subjects: African Americans; Blood Group Antigens - genetics; Blood groups; Complement receptor 1; complement receptors; CR1 gene; Erythrocytes; Erythrocytes - immunology; Erythrocytes - parasitology; Female; Gene Frequency; Genes; Genotype & phenotype; Humans; Ligands; Malaria; Malaria, Falciparum - genetics; Malaria, Falciparum - immunology; Male; Mali; Molecular Weight; Pedigree; Phenotypes; Plasmodium falciparum; Polymorphism; Polymorphism, Genetic; Receptors, Complement 3b - chemistry; Receptors, Complement 3b - genetics; United States; West Africa; Mali; United States; United States > US; Africa; Africa, West
• ISSN: 1466-4879; 1476-5470
• DOI: 10.1038/sj.gene.6363676

Complement receptor one (CR1) is a ligand for the rosetting of Plasmodium falciparum infected red cells with uninfected cells. Since CR1 exhibits three known polymorphisms, we studied European-Americans (n = 112) and African-Americans (n = 330) and Malians (n = 158) to determine if genetic differences existed in an area endemic for malaria that could offer a survival advantage. The frequencies of Knops blood group phenotypes McC(b+) and Sl(a-) were greatly increased in Africans vs Europeans. Although the frequency of McC(b+) was similar between Africans from the USA or Mali, the Sl(a-) phenotype was significantly higher in Mali (39% vs 65%, respectively). There was an increased frequency of the largest size (250 kD) of CR1 in Mali, but this did not differ significantly from the USA (P = 0.09). Both cohorts of Africans had higher expression of red cell CR1 than European-Americans but this showed little difference between the USA and Mali groups. Thus, the most important CR1 polymorphism relevant to rosetting of malaria infected cells appears to be the Knops blood group.