T-CELL SUB-POPULATIONS FOLLOWING THERMAL-INJURY

Abstract

Human T-cell subsets were enumerated as defined by receptors for Ig isotypes at 24-48 h postburn. T cells possessing surface receptors for the Fc fragment of IgM represent a population of cells with helper activity, T.mu. cells, and T cells possessing surface receptors for the Fc fragment of IgG represent a population of cells with suppressor-cytotoxic function, T.gamma. cells. Significant alterations in the number and proportion of regulatory T cells was observed early in the course of severe burn trauma. A decrease in total T cells was accompanied by a drop in IgM-Fc binding lymphocytes, helper cells, in all burns > 20% total body surface area. An increase in IgG-Fc binding lymphocytges was observed only in those patients who had sustained the most severe injuries, > 60% total body surface area burn or > 25% third-degree burn. These changes correlated linearly with the amount of full thickness injury, and the ratio of T.mu.:T.gamma. cells was significant at 24-48 h postburn in predicting the risk of septic death.