Interleukin 17D is a disulfide-linked homodimer belonging to the IL-17 family of proinflammatory cytokines. Members belonging to this family share conserved features of cysteine-knot structures but differ in their N-terminal regions. The T-helper cell produced IL17 family is inducible by IL15 and IL23, and IL17D induces expression of endothelial IL6, IL8, and GM-CSF, and inhibits hemopoiesis of myeloid progenitor cells.