Among CD3+ T cells, the median percentage of CD4+CD25hi T cells (Fig. 2A) in the uninfected malaria-exposed controls was significantly higher (3%, N = 17) than that of the unexposed controls (2%, N = 21, MD = 0.9, 95%CI = 0.1–1.7, P = 0.02). Here, CD4 is linked to malaria.