IL31 and primary cutaneous T-cell non-Hodgkin lymphoma: We provided several lines of evidence for a critical contribution of this signaling pathway in the mouse CTCL model: (a) Il31ra was upregulated in Trpv1+ neurons in CTCL mice on days 20, 40, and 60; (b) IL-31 levels were significantly increased in lymphomas; and (c) a single intratumoral injection of IL-31–neutralizing antibody suppressed CTCL-induced pruritus for more than 24 hours.