IL-8 is a recently described chemokine that increases polymorphonuclear neutrophil infiltration and has been implicated in inflammatory pathology. This study assesses monocyte (MØ) interleukin-8 (IL-8) levels in severe trauma patients (injury severity score 16) who have elevated levels of MØ cell-associated tumor necrosis factor a (TNFα), a major marker for systemic inflammatory response syndrome after injury. We demonstrate elevated (p = .0007) levels of MØ IL-8 only in those trauma patients who also have increased (p = .0001) MØ-secreted TNFα whereas the patients having normal MØ-secreted TNFα levels have normal or even decreased MØ IL-8 production. There is no association between MØ IL-8 production and cell-associated TNFα levels. MØ induction by FcRIcross-linking, a common induction pathway in trauma patients' MØ that increases the production of both cell-associated and secreted TNFα, can also increase (p = .0022) MØ IL-8 levels. Therefore, post-trauma elevation of MØ IL-8 levels may be associated with increased secreted TNFα resulting from, at least in part, FcγRI cross-linking stimulationin vivo.
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