The purpose of the study is to evaluate the status and function of gamma delta T cells in peripheral blood of sepsis patients.

Sepsis therapy is a prominent problem of the modern critical care medicine,and improving the level of sepsis treatment by immune intervention measures is a hot research topic with close attention.Gamma delta T cells is considered as one new T lymphocyte subset in recent years,which playing an important role in resistance to infection,anti-tumor and immune regulating function in the body.First,we played attention to the status and function of gamma delta T cells in peripheral blood of sepsis patients including differentiation marker,subtype and production of related cytokine,and then the molecular mechanism of insufficient gamma delta T cells.At the same time the responsibility of gamma delta T cells of sepsis patients to certain bacteria and viral antigen and the regulation of gamma delta T cells on other natural immune cells including NK cells and mononuclear cells were studied to identify the status and role gamma delta T cells in sepsis immunosuppression by culture in vitro.Further we studied the effect of specific stimulants on proliferation and activation of gamma delta T cells in patients with sepsis and also anti-infection acquired by gamma delta T cells,expecting as an entry point to explore new treatment strategy to sepsis.

Inclusion Criteria:

• clinical symptoms of severe sepsis and septic shock
• age over 18 years

Exclusion Criteria:

• preexisting autoimmune disease
• patients received immuno-suppressive treatment in the previous 6 months
• patients with chronic infection,e.g.tuberculosis,hepatitis or HIV infection,etc.
• pregnancy

Patients admitted in ICUs of West China Hospital