IL17A and psoriasis: IL-17 upregulates chemokines and metalloproteases, which stimulate neutrophile recruitment and IL-17 blocking agents have been successfully used to treat psoriasis (Liang et al. 2006; Nograles et al. 2008; Lee et al. 2008; Ly et al. 2019) and also MS (Havrdová et al. 2016).