Th17 pathogenic

Th17 pathogenic refers to a distinct phenotype of Th17 cells which is associated with immunopathology. The development of the pathogenic phenotype can be shaped by various environmental stimuli and genetic factors. In humans, Th17 pathogenic cells are associated with diseases like multiple sclerosis (MS) or rheumatoid arthritis (RA) and in mice with experimental autoimmune encephalomyelitis (EAE). Th17 pathogenic cells are known to display pro-inflammatory features like expressing transcription factor T-bet and secreting cytokine IFNγ, resembling Th1-like phenotype. Th17 cells are a very heterogenous subset and can switch to display all T helper-like phenotype markers including those typical for Th2, Treg and Tfh.

Th17 cells gain the pathogenic phenotype by induction with pro-inflammatory cytokines IL-1β, IL-6 and IL-23 during their maturation. On the other hand, regulation of the Th17 immune response by TGFβ1 and IL-10 is known to inhibit Th17 pathogenicity. GM-CSF and IL-17 were recognised as the main effector cytokines secreted by Th17 pathogenic cells that promote the development of immunopathology.