TACR1 and psoriasis: SP is secreted by nerves and inflammatory cells and acts by binding to the neurokinin-1 receptor (NK-1 R) having a proinflammatory effect in psoriasis [2] and stimulates chemotaxis of lymphocytes and neutrophils [3] and promotes T helper 17 (Th17) to produce interleukin-17 (IL-17) [4].