CD4 and malaria: Immunohistochemical staining revealed that CD4+Foxp3+ Tregs are located almost exclusively in the T cell areas of the white pulp within 6 days p.i. and are still evident on day 10 p.i. To address if CXCR3 is expressed differentially on CD4+ T cell populations during blood-stage malaria, we examined CXCR3 expression on CD4+Foxp3− and CD4+Foxp3+ T cells (Supplementary Figure 1A).