α+-thalassemia protects African children from severe malaria
2004; Elsevier BV; Volume: 104; Issue: 7 Linguagem: Inglês
10.1182/blood-2003-11-4090
ISSN1528-0020
AutoresFrank P. Mockenhaupt, Stephan Ehrhardt, Sabine Gellert, Rowland N. Otchwemah, Ekkehart Dietz, Sylvester D. Anemana, Ulrich Bienzle,
Tópico(s)Parasites and Host Interactions
ResumoAbstract The high frequency of α+-thalassemia in malaria-endemic regions may reflect natural selection due to protection from potentially fatal severe malaria. In Africa, bearing 90% of global malaria morbidity and mortality, this has not yet been observed. We tested this hypothesis in an unmatched case-control study among 301 Ghanaian children with severe malaria and 2107 controls (62% parasitemic). In control children, α+-thalassemia affected neither prevalence nor density of Plasmodium falciparum. However, heterozygous α+-thalassemia was observed in 32.6% of controls but in only 26.2% of cases (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.56-0.98). Protection against severe malaria was found to be pronounced comparing severe malaria patients with parasitemic controls (adjusted OR in children < 5 years of age, 0.52; 95% CI, 0.34-0.78) and to wane with age. No protective effect was discernible for homozygous children. Our findings provide evidence for natural selection of α+-thalassemia in Africa due to protection from severe malaria.
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