IL17A and psoriasis: Previous studies supported the finding of the importance of the IL17/IL22/IL23 axis in the pathogenesis of psoriasis, where IL23 is reported not only to support the Th17 lymphocyte producing IL-17 (McGeachy et al. 2009), but also stimulate IL-17 production via innate T lymphocyte such as Gamma delta T lymphocytes (Tγδ) (Qi et al. 2021).