A major difference between Fulani and Mossi was the frequency of CD4+CD25+high cells that were predominant in Fulani group at the peak of malaria transmission season (2.92% in Fulani and 1.91% in Mossi) with a p = 0.03 (Figure 1), but remained similar at the low transmission season (3.3% in Fulani and 2.75% in Mossi, p = 0.47). Here, CD4 is linked to malaria.