A PROSPECTIVE-STUDY OF THE INFLUENCE OF ALPHA-THALASSEMIA ON MORBIDITY FROM MALARIA AND IMMUNE-RESPONSES TO DEFINED PLASMODIUM-FALCIPARUM ANTIGENS IN GAMBIAN CHILDREN

The protective effect of alpha thalassaemia (-alpha/alphaalpha) agains t morbidity from falciparum malaria was assessed in a prospective stud y of rural Gambian children. The gene frequency for single alpha-globi n gene deletions was 0.12. Malariometric indices measured during cross -sectional surveys and morbidity from malaria determined by weekly sur veillance were similar in children with alpha thalassaemia and in thos e with a normal alpha-globin genotype. However, the small number of ch ildren who carried both alpha thalassaemia and the sickle cell trait h ad fewer clinical episodes of malaria than children with the sickle ce ll trait alone. Specific antibody responses and cell-mediated immune r esponses in vitro to defined Plasmodium falciparum antigens were measu red in children participating in the study. In general, there was no e vidence of an increased prevalence or intensity of humoral or cell-med iated immune responses to the malaria antigens studied in children het erozygous for alpha thalassaemia compared with children with a normal alpha-globin genotype.