A prospective study of the influence of α thalassaemia on morbidity from malaria and immune responses to defined Plasmodium falciparum antigens in Gambian children

The protective effect of α thalassaemia against morbidity from falciparum malaria was assessed in a prospective study of rural Gambian children. The gene frequency for single α-globin gene deletions was 0·12. Malariometric indices measured during cross-sectional surveys and morbidity from malaria determined by weekly surveillance were similar in children with α thalassaemia and in those with a normal α-globin genotype. However, the small number of children who carried both α thalassaemia and the sickle cell trait had fewer clinical episodes of malaria than children with the sickle cell trait alone. Specific antibody responses and cell-mediated immune responses in vitro to defined Plasmodium falciparum antigens were measured in children participating in the study. In general, there was no evidence of an increased prevalence or intensity of humoral or cell-mediated immune responses to the malaria antigens studied in children heterozygous for a thalassaemia compared with children with a normal α-globin genotype. © 1993 Oxford University Press.