IL17A and graft versus host disease: For instance, IFN-γ can mediate separate functions at the same target organ during Graft-versus-host disease (GVHD), and IL-17 can induce the expression of proinflammatory tumor necrosis factor (TNF)-α, chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1 to promote tissue inflammation [30–32].