IL4 and acute lymphoblastic leukemia: In a study by Zhang et al. on the IL-4-producing CD4+ (Th2) and CD8+ (Tc2) subpopulations, it was demonstrated that the Th1/Th2 and Tc1/Tc2 ratios were significantly decreased in the peripheral blood T cells of ALL patients (n = 30) compared to the healthy controls, suggesting the dysregulated differentiation of Th2 and Tc2 in these patients [18].