IL-17A AND IL-17F ARE PRODUCED BY THE INNATE AND ADAPTIVE IMMUNE SYSTEM
T17 cells secrete IL-17A and IL-17F, both of which are present as homodimers and heterodimers and play critical overlapping roles in psoriasis pathogenesis.1
Most IL-17 family subtype cytokines are elevated in psoriasis. The abundance of IL-17F in psoriatic skin compared to non-lesional skin is more elevated than IL-17A. Both are important proinflammatory cytokines in the pathogenesis of psoriasis.1,11,12
The expression of T17 cells both in circulation and in lesional skin has been shown to correlate clinically with the severity of psoriasis.1 IL-17A and IL-17F are produced by not only T17 cells but also cells of the innate-like immune system, such as γδ T cells and ILC3.8,10