Inflammatory cytokines such as IL-31 produced by Th2 lymphocytes, immune reactive cells, various skin cells, not to mention both central and peripheral neuronal networks, where tachykinin, a neuropeptide released from mast cells, may bind to various neurokinin receptors (NK1R, NK2R, NK3R), might be involved in pruritus development [12,13,14,15]. The gene discussed is IL31; the disease is Pruritus.