Chemokines. Act primarily as chemoattractants for specific types of leukocytes. Stimulate leukocyte recruitment in inflammation. Control normal migration of cells through various tissues. Acute phase response or reactions to cytokines(Systemic Inflammatory Response Syndrome) Fever- produced in response to pyrogens (LPS- IL-6, lipopolysacchide induces interleukin 6 ) and TNF causing increase in PGE-2- this affects temperature center in hypothalamus.