CCR4 and neoplasm: ,16,17 Especially in solid tumors, regulatory T cell (Treg; CD25+CD4+) depletion using anti-CCR4 monoclonal antibody (mAb) or anti-CCR8 mAb is effective in reducing tumor-infiltrating effector Tregs (eTregs) and in enhancing antitumor activity,28,29 suggesting that depleting these cells from infusions could be advantageous.