CD4 and neoplasm: Expressions of IL-2 and IL-2 receptor by CD8+ cytotoxic T lymphocytes (CTLs) and tumor-infiltrating lymphocytes (TILs) were also reduced under the influence of PGE2, while PGE2 induced CD4+ Th2 cell activation (Wustrow and Mahnke, 1996; Li et al., 2013).