Distinctive features of classic and nonclassic ( T h17 derived) human T h1 cells

T helper17 ( T h17) lymphocytes represent a third arm of the CD 4 + T ‐cell effector responses, in addition to T h1 and T h2 cells. T h17 cells have been found to exhibit high plasticity because they rapidly shift into the T h1 phenotype in inflammatory sites. In humans, T h1 cells derived from T h17 cells express CD 161, whereas classic T h1 cells do not; these T h17‐derived T h1 cells have been termed nonclassic T h1 cells. In this study, we examined similarities and differences between classic and nonclassic human T h1 cells by assessing a panel of T ‐cell clones, as well as CD 161 + or CD 161 − CD 4 + T cells derived ex vivo from the circulation of healthy subjects or the synovial fluid of patients with juvenile idiopathic arthritis. The results show that nonclassic T h1 cells can be identified based on CD 161 expression, as well as the consistent expression of retinoic acid orphan receptor C , IL ‐17 receptor E , CCR 6, and IL ‐4‐induced gene 1, which are all virtually absent in classic T h1 cells. The possibility to distinguish these two‐cell subsets by using such a panel of markers may allow the opportunity to better establish the respective pathogenic roles of classic and nonclassic ( T h17 derived) T h1 cells in different chronic inflammatory disorders.