CD4 and acute lymphoblastic leukemia: We observed that the frequency of ALL−CD25+Foxp3+CD4+ T cells was increased 66.7 times in Con A-stimulated cells when they were compared to nonstimulated cells (P = 0.007), whereas the frequency of ALL+CD25+Foxp3+CD4+ T cells was increased 2-times in ConA-stimulated cells as compared to nonstimulated cells (P = 0.036) (Figure 5(a)).