The IL-17/IL-17R axis has a role even in chronic pain in RA, as emerged from experimental data in a mouse model of neuropathic pain elicited by partial ligation of the sciatic nerve, in which the IL-17 knock-out mice demonstrated significantly lower pain hypersensitivity, decreased infiltration of T cells and macrophages into the sciatic nerve, and decreased activation of microglia and astrocytes in the L3–L5 dorsal and ventral horns of the spinal cord. The gene discussed is IL17A; the disease is rheumatoid arthritis.