IL17A and psoriasis: In both psoriasis patients and healthy individuals the total percentage of Th17 cells exceeded that of Tc17 cells (psoriatic skin: Th17 8.89%±1.88%, Tc17 3.39%±0.70%; normal skin: Th17 9.18%±3.13%; Tc17 0.35%±0.17%), which is consistent with our data on IL-17A expression by T cells in peripheral blood (unpublished observation).