Therapeutic immunomodulatory approaches for the control of systemic inflammatory response syndrome and the prevention of sepsis

Abstract

In the sequelae of massive traumatic stress, substantial impairment of immunologic reactivity has been demonstrated to correlate clinically with increased susceptibility to serious infection. Posttraumatic immune abnormalities consist basically of two coexistent mechanisms: Hyperinflammation and depression of cell-mediated immune responses. It is our understanding that the endogenous ability of the organism to survive overwhelming trauma is insufficient and requires exogenous support to prevent the conversion from systemic inflammatory response syndrome to bacterial sepsis and septic shock. The objectives of immunomodulatory interventions, which should be started as early as possible after tissue destruction, include a) prevention of excessive macrophage stimulation via neutralization of circulating endotoxins and exotoxins with high doses of polyvalent immunoglobulin and soluble complement receptors, b) global short-term (<72 hrs) down-regulation of inflammatory monocyte/macrophage and polymorphonuclear neutrophil activity, and c) restoration of cell-mediated immune performance to overcome posttraumatic functional paralysis. Among recent promising strategies, the use of granulocyte-macrophage colony-stimulating factor, pentoxifylline, and recombinant human interleukin-13 has been suggested, all of them predominantly down-regulating the Mphi (monocyte/macrophage) inflammatory potential. Cyclooxygenase inhibitors such as indomethacin and thymomimetic peptides can help normalize the immunoreactivity by restoring the forward-regulatory pathway of cell-mediated immunity responses. The efficacy of interferon to reduce infection and deaths in severely injured patients has been assessed in clinical trials. Still other compounds, i.e., CNI-1493, interleukin-11, tissue factor pathway inhibitors, and PGG-Glucan represent auspicious immunomodulatory approaches for control of posttraumatic or postoperative infections.