The imbalance between anti- and pro-inflammation often occurs in patients with sepsis. And continuous such imbalance could lead to immunoparalysis, which is characterized by loss of delayed type hypersensitivity, failure of primary infections eradication, and a predisposition of secondary nosocomial infections development. However, in which phase of sepsis does immunoparalysis occur is still unknown. So this study aims to tentatively understand this problem by checking monocytes/macrophages' antigen presentation and cytokine secretion，and by checking monocytes/macrophages' expression of Tim-3 (the T cell transmembrane, immunoglobulin, and mucin-3), which is an inhibitory regulatory molecule, in sepsis patients' peripheral blood mononuclear cells.

Inclusion Criteria:

• age over 18 years old;
• Fulfilled at least two criteria of systemic inflammatory response syndrome (a) core temperature higher than 38 ℃ or lower than 36 ℃ (b)respiratory rate above 20/min, or carbon dioxide partial pressure below 32 mmHg (c) pulse rate above 90/min, and (d) white blood cell count greater than 12,000/μl or lower than < 4,000/μl or less than 10% of bands.
• Clinically suspected infection;

Exclusion Criteria:

• were under 18 years of age;
• were refused by the patients or his/her familiality;
• were suffering from acquired immunodeficiency syndrome,viral hepatitis,autoimmune diseases and hematology;
• use medicine which can affect immune system,such as Glucocorticoid and Immunosuppressant
• died within 24h after being taken into the ICU, or refused to get involved in the study, or gave up treatment during the period of observation

All subjects were selected from among inpatients who were hospitalized between August 2012 and March 2013 in the Respiratory ICU, Surgical ICU, and Emergency ICU, Chinese People's Liberation Army (CPLA) General Hospital.