Frequency of BDCA3-Positive Dendritic Cells Is Increased in the Peripheral Circulation of Kenyan Children with Severe Malaria

The ability of Plasmodium falciparum-infected erythrocytes to adhere to host endothelial cells via receptor molecules such as ICAM-1 and CD36 is considered a hallmark for the development of severe malaria syndromes. These molecules are also expressed on leukocytes such as dendritic cells. Dendritic cells are antigen-presenting cells that are crucial for the initiation of adaptive immune responses. In many human diseases, their frequency and function is perturbed. We analyzed the frequency of peripheral blood dendritic cell subsets and the plasma concentrations of interleukin-10 (IL-10) and IL-12 in Kenyan children with severe malaria and during convalescence and related these parameters to the adhesion phenotype of the acute parasite isolates. The frequency of CD1c⁺ dendritic cells in children with acute malaria was comparable to that in healthy controls, but the frequency of BDCA3⁺ dendritic cells was significantly increased. Analysis of the adhesion phenotypes of parasite isolates revealed that adhesion to ICAM-1 was associated with the frequency of peripheral blood CD1c⁺ dendritic cells, whereas the adhesion of infected erythrocytes to CD36 correlated with high concentrations of IL-10 and low concentrations of IL-12 in plasma.