The fully competent IL-6R consists of an alpha subunit IL-6R (CD126) and a commonly expressed beta subunit gp130 (CD130).152,153 Recent evidence demonstrates that IL-6 can initiate the development of Th17 cells.154 The IL-17 generated by Th17 cells can feedback regulate the production of IL-6 of keratinocytes.83 The positive feedback loop of IL-6/IL-17 signaling participates in the proinflammatory interaction of innate and adaptive immunity in patients with psoriasis. This evidence concerns the gene IL17A and psoriasis.