Dynamics of T-lymphocyte subpopulations and T-lymphocyte function following thermal injury

Abstract

The study was designed to evaluate T-lymphocyte function in relation to the numbers of T cells present in patients that had sustained major thermal injury. Also, it was designed to determine the dynamics of total T cells and the T-cell subpopulation that formed `active' E rosettes in separated cell populations. The primary observations were: (a) within 10 days of injury a significant depression of T-cell numbers in separated cell populations occurred, which was paralleled by a decrease in T-cell function. Thus the immunosuppression that has been observed in burn patients appears to have been related to decreases in the numbers of T cells, rather than to any dysfunction at the level of the individual T cell; (b) although T-cell numbers remained depressed, in some patients mitogen responses returned to very high levels, suggesting the possibility that either a highly responsive T-cell subpopulation was selected or that there was a depletion of suppressor cells; (c) in patients that survived there was a gradual return of T lymphocyte numbers to normal levels; and (d) the decreases in the total T-cell population were accompanied by a depletion of the T cells that formed `active' (37°C stable) rosettes, and the recovery of normal T-cell numbers was accompanied by a disproportionate increase in `active' rosette-forming cells. The high numbers of `active' rosettes during the recruitment of new T cells suggested that this T-cell subpopulation may represent cells recently arrived in the peripheral blood from the precursor pools.