Increased levels of soluble ST2 protein and IgG1 production in patients with sepsis and trauma

Objective. T1/ST2, a member of the interleukin (IL)-1 receptor superfamily, is predominantly expressed on type-2 T helper (Th2) cells but not Th1 cells, and plays a role in cell proliferation and Th2 immune response. The relation of soluble ST2, Th1-Th2 cytokine profile, and immunoglobulin (Ig) production in sepsis and trauma patients is not well known. Design and setting. Case-control study at a university hospital intensive care unit. Patients. Fifteen patients recruited within 24-48 h of diagnosis of sepsis, 13 trauma patients recruited within 24 h after admission to the ICU, 11 patients who underwent abdominal surgery, and 15 healthy volunteers served as control. Measurements and results. ELISA was utilized to detect serum soluble ST2, IL-2, IFN-gamma, IL-10, and Ig production. Serum levels of soluble ST2 were significantly increased in septic patients (8420+/-2169 pg/ml) as compared with trauma (2936+/-826 pg/ml), abdominal surgery (1423+/-373 pg/ml), and healthy controls (316+/-72 pg/ml; p<0.001, respectively). These results were accompanied by an increase of IgG1 and IgG2 production, and decrease of IL-2 and IFN-gamma synthesis in septic patients. IL-10 was significantly increased in both septic and trauma patients. Conclusions. Our results demonstrate that soluble ST2, a marker for Th2 cytokine producing cells, is increased in sepsis and trauma patients, and they provide further evidence for a shift from Th1- to Th2-biased cells.