Impaired cell-mediated immunity in the first week after burn injury: investigation of spontaneous blastogenic transformation, PHA, IL-2 response and plasma suppressive activity

Abstract

This study investigated alterations of cell-mediated immunity induced by trauma, operative treatment and infections in a group of 19 burned patients with a mean burn size of 42±22 per cent of the body surface area. We tested peripheral mononuclear blood cells (PMBC) for spontaneous blastogenic transformation (SBT), phytohaemagglutinin (PHA) and interleukin-2 (IL-2) responsiveness. Plasma samples were also assayed for inhibition of mitogen stimulation of control PMBCs. Mean values were calculated for the acute postburn period (days 0–3) and the following 4 days, before the development of septic complications. SBT was significantly increased in all patients during the second period of investigation (days 4–7) in comparison to normal controls and during the acute phase. The response to mitogen stimulation (PHA) was significantly suppressed during days 0–7 and the plasma samples showed high suppressive activities following PHA stimulation of control lymphocytes during the course of the study. No significant differences in rates of SBT, PHA responsiveness and plasma suppressive activity were found between those patients who developed bacteraemia and those with negative blood cultures. The latter group showed higher reactivity to added IL-2 in comparison to normal controls. Surgical treatment immediately after trauma (fasciotomy; day 0 or 1) resulted in further increased immunosuppression (PHA and IL-2 response), whereas after necrectomy (days 4–7) the immunological parameters showed no significant differences. It can be concluded that neither rates of SBT nor response to PHA can be used to identify patients at high risk for infection during the first week postburn. In each case moderate to severe impairment of lymphocyte reactivity and in particular reduced response to IL-2 was associated with high plasma immunosuppressive activity.