ALTERED T-CELL CYTOKINE PRODUCTION FOLLOWING MECHANICAL TRAUMA

Background: Cell mediated immunity is suppressed following traumatic i njury. The objective is to deter mine whether there is a shift from T helper type 1 (T(H)1) to T(H)2 cell cytokine production following mech anical trauma in a rat model. Methods: Male Sprague-Dawley rats were a nesthetized and subjected to bilateral femur fractures or sham injury. Spleens were removed 3 days later. T cell proliferation and cytokine production were stimulated by culturing spleen cells with the T cell m itogen concanavalin A (con A). Interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-10 and IL-4 concentrations were measured in spleen cel l supernatants using enzyme linked immunosorbent assays. Results: Con A-induced spleen cell proliferation was decreased in traumatized rats compared to controls (p < 0.05). Spleen cell supernatant concentration s of the T(H)1 cytokines IL-2 and IFN-gamma were decreased in the trau ma group (p < 0.05). Supernatant concentrations of the T(H)2 cytokine IL-10 were also decreased in traumatized rats (p < 0.01). The IL-4 con centrations were below the detection limit (<15 pg/mL) in all cell sup ernatants. Conclusions: Mechanical tissue injury leads to generalized suppression of T helper cell cytokine production rather than a shift f rom T(H)1 to T(H)2 cell activity. Post-trauma cellular immunosuppressi on is not mediated via excess IL-10 production by T(H)2 cells.