CD4 and neoplasm: Moreover, tumors may condition local DCs to form suppressive T cells, such as Tregs, IL-13-producing CD4+ T cells and natural killer T cells (NKT cells), leading to a tumor-induced functional deficiency of DCs that results in decreased expression of costimulatory molecules, decreased production of IL-12, suppressed endocytic activity, inhibited antigen-processing machinery, and poor viability (73–77).