CD4 and leukemia: In this sense, the increased levels of IL-2, together with IFN-γ observed in LR and MRD(-), may support a potent and balanced T-cell response that, together with enhanced levels of CCL5, participate in the recruitment, activation and migration of CD4+ and CD8+ T-cells and NK-cells (26, 27), and ultimately favor the elimination of leukemia cells.