CD4 and malaria: Given our previous observation of Treg expansion during the pre-patent phase of malaria infection [27], we suggest that Tregs are induced/activated shortly after parasite emergence from the liver, that their numbers in peripheral blood then decline as a result of sequestration of CD4+ T cells during acute disease [40],[41],[56] and then, as has been described for other T cell subsets [39],[57], Tregs regain access to the circulation after malaria is cured.