Plasmodium falciparum malaria causes morbidity and mortality in African children with
sickle cell anemia (SCA), but comparisons of host responses to P falciparum between children with SCA (homozygous
sickle cell disease/
hemoglobin SS [HbSS]) and normal
hemoglobin genotype/
hemoglobin AA (
HbAA) are limited. We assessed parasite biomass and plasma markers of
inflammation and endothelial activation in children with
HbAA (n = 208) or HbSS (n = 22) who presented with severe
anemia and P falciparum
parasitemia to Mulago Hospital in Kampala, Uganda. Genotyping was performed at study completion. No child had known SCA at enrollment. Children with HbSS did not differ from children with
HbAA in peripheral parasite density, but had significantly lower sequestered parasite biomass. Children with HbSS had greater
leukocytosis but significantly lower concentrations of several plasma inflammatory
cytokines, including
tumor necrosis factor α (TNF-α). In contrast, children with HbSS had threefold greater concentrations of
angiopoietin-2 (Angpt-2), a marker of endothelial dysregulation associated with mortality in severe
malaria. Lower TNF-α concentrations were associated with increased risk of postdischarge mortality or readmission, whereas higher Angpt-2 concentrations were associated with increased risk of recurrent clinical
malaria. Children with SCA have decreased parasite sequestration and
inflammation but increased endothelial dysregulation during severe
anemia with P falciparum
parasitemia, which may ameliorate acute infectious complications but predispose to harmful long-term sequelae.