Immunological activity change of regulatory T cells and its relation with outcome of patients with severe burn / 中华创伤杂志

ABSTRACT

Objective To investigate the immunological activity change of regulatory T cells (Treg) and discuss its significance in the outcomes of patients with multiple organ dysfunction syndrome (MODS) and severe burn. Methods A total of 106 patients with total burn surface area (TBSA) larger than 30% were included in the study and randomly divided into three groups according to the burn area Group Ⅰ (TBSA of 30%-49%, n = 41), Group Ⅱ (TBSA of 50% -69%, n = 34) and Group Ⅲ (TBSA of 70%-99%, n = 31). According to the development of MODS, patients were divided into MODS group (n =21) and non-MODS group (n =85). The patients with MODS were further divided into non-survival group (n = 16) and survival group (n = 5) based on their outcomes. Healthy volunteers were served as normal control (n = 25). Peripheral blood samples were collected at days 1,3,7, 14 and 21 postburn. The immunomagnetic separation technique was applied to separate and purify CD4+ CD25+Tregs in peripheral blood, and phenotypes (CTLA-4) were analyzed by flow cytometry and the contents of interleukin-10 released in the supernatants were determined by ELISA. Results Expression of CTLA-4 and level of IL-10 were significantly increased in burn patients compared with normal control group, with statistical differences. The expression of CTLA-4 and level of IL-10 were significantly increased in patients with severe burns at all time points. The expression of CTLA-4 and level of IL-10 in MODS group were much higher than those in non-MODS group at days 3-21 postburn (P ＜ 0.01). Among the MODS patients, the expression of CTLA-4 and level of IL-10 in the survival group were obviously lower than those in the non-survival group at days 3-21 postburn (P ＜ 0.05 or P ＜ 0.01). Conclusions After severe burn injury, expressions of the markers on CD4 + CD25 + Treg surface and secretion of cytokines produced by CD4 + CD25 + Tregs show significant difference in patients with different born areas, MODS development and survival state. CD4 + CD25 + Treg may play an important role in the pathogenesis of immunoregulation, MODS and mortality of burn patients through secretion of inhibitory cytokines.