IL2 and melanoma: Clinically, high-dose interleukin-2 (HD IL-2) has been employed for the treatment of advanced melanoma and renal cell carcinoma (136, 137), whereas low-dose recombinant human IL-2 selectively modulates the abundance of regulatory T (Treg) cells, follicular helper T (TFH) cells and IL-17-producing helper T (TH17) cells (138).