Table 1.

Complexities and questions in the biology of Th17 cells

AreaComplexities and Questions
Th17 cell plasticityDo Th17 cells later acquire a Th1 phenotype?
Is it inevitable that some Tregs will become Th17 cells in inflammation?
Th17 does not equal IL-17AWhat are the roles of other Th17 cytokines?
IL-17A does not equal Th17Other important cellular sources of IL-17A need to be assessed
Relationships between Th1 and Th17Do Th1 and Th17 cells synergize with or antagonize each other?
Differences between mice and men?How discrete is the Th17 subset in humans?
Renal injury mediated by Th17 responsesDo effector Th1 and Th17 responses reflect different pathways to similar renal end points?
Intrinsic kidney cells and Th17 cellsHow do renal cells respond to (and potentially secrete) Th17 cytokines?
Further Th subsets (for example, Th22 and Th9)How many subsets are there?
Is there a continuum between them?