Hypertonicity rescues T cells from suppression by trauma-induced anti-inflammatory mediators

Trauma causes the release of anti-inflammatory factors thought to cause inf ections by inhibiting T cells. We have found that hypertonic saline (HS) en hances functions of normal T cells. Here we studied if HS can rescue T cell s from suppression by costimulating interleukin (IL)-2 production. Human pe ripheral blood mononuclear cells were treated with the immunosuppressive fa ctors IL-4, IL-10, transforming growth factor (TGF)-beta (1), and PGE(2) an d with serum of trauma patients and stimulated with phytohemagglutinin, and IL-2 production was measured. Costimulation with HS tripled IL-2 productio n of normal cells. IL-4, IL-10, TGF-beta (1), and PGE(2) suppressed IL-2 pr oduction with IC50 of 500, 1, 36,000, and 0.01 pg/ml, respectively. Costimu lation of suppressed cells with HS restored IL-2 production and increased I C50 values >70-fold. Serum from trauma patients could completely suppress n ormal cells; however, costimulation with HS restored IL-2 production by up to 80% of the control response. These findings show that HS can restore the function of suppressed T cells, suggesting that HS resuscitation of trauma patients could reduce posttraumatic sepsis.