title: Frequencies of peripheral blood myeloid cells in healthy Kenyan children with alpha+ thalassemia and the sickle cell trait.
abstract: The high frequencies of both alpha+ thalassemia and the sickle cell trait (hemoglobin AS [HbAS]) found in many tropical populations are thought to reflect selection pressure from Plasmodium falciparum malaria. For HbAS, but not for alpha+ thalassemia, protection appears to be mediated by the enhanced phagocytic clearance of ring-infected erythrocytes. We have investigated the genotype-specific distributions of peripheral blood leukocyte populations in two groups of children living on the coast of Kenya: a group of healthy P. falciparum parasite-negative children sampled at cross-sectional survey during a period of low malaria transmission, and a group of children attending the hospital with acute malaria. We report distinctive distributions of peripheral blood myeloid dendritic cells and monocytes in children with alpha+ thalassemia and HbAS during healthy periods and disease, and suggest ways in which these might relate to the mechanisms of protection afforded by these conditions.
authors.affiliation: Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Churchill Hospital, Oxford, United Kingdom. britta.urban@ndm.ox.ac.uk
authors.forename: Britta C
authors.initials: BC
authors.lastname: Urban
authors.forename: Mohammed J
authors.initials: MJ
authors.lastname: Shafi
authors.forename: Damien V
authors.initials: DV
authors.lastname: Cordery
authors.forename: Alex
authors.initials: A
authors.lastname: Macharia
authors.forename: Brett
authors.initials: B
authors.lastname: Lowe
authors.forename: Kevin
authors.initials: K
authors.lastname: Marsh
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Williams
mesh_terms: D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005434:Flow Cytometry; D005838:Genotype; D006451:Hemoglobin, Sickle / Q000235:genetics; D006801:Humans; D007223:Infant; D007630:Kenya / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D022423:Myeloid Cells / Q000166:cytology*; D012805:Sickle Cell Trait / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D017085:alpha-Thalassemia / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000235:genetics*
chemical_list: D006451:Hemoglobin, Sickle