CD4 and precursor B-cell acute lymphoblastic leukemia: Previous studies have suggested that some immune cells could predict the prognosis of all patients, for example, Hohtari et al. [10] and Zhou et al. [11] found that the proportion of PD1+TIM3+ double-positive CD4+ T cells could differentiate the poor survival group of B-ALL, and Duault et al. [12] revealed that increased frequencies of activated cytokine-producing NK cells could independently predict poor clinical outcome in ALL patient.