In addition to Th1 cells, Th17 cells have been shown to express TIM-3, but at a lower level than on Th1 cells.101 In patients with psoriasis, TIM-3-negative Th1 and Th17 cells are increased in the peripheral blood, suggesting that impaired TIM-3 expression allows Th17 and Th1 cells to escape from TIM-3-mediated immunoregulation and thereby mediate disease.98 Together, these studies indicate that manipulating TIM-3 signaling in vivo may be a valuable tool in the treatment of autoimmunity. This evidence concerns the gene HAVCR2 and psoriasis.