Sepsis remains a common entity in critical care patients with remarkable mortality. Pulmonary and abdominal infections (with subsequent sepsis) are the most common in the ICU. Despite extended research activities, no differences in patient outcome or organ dysfunction were revealed.

Sepsis is a complex immune reaction phenomenon based on unbalanced activation and suppression. In addition to changes of cytokine levels and immune cell activity, underlying genetic reactions are present. For instance, expression of miRNA (as a potential important step of immune cell activation) is likely changed during systemic and local immune reactions.

The aim of this study is to perform a detailed assay of immune cell activation, to investigate the levels of pro- and antiinflammatory cytokines and the various expression of miRNA depending on the origin of infection in the two most common sides. This means in ICU patients with early pulmonary or abdominal sepsis as well as in healthy controls. Additionally, clinical parameters of organ function, current infection markers as CRP and procalcitonin, cardiovascular function and heart rate variability will be assessed. Parameters of local tissue perfusion in a dynamic testing during forearm ischemia and plasma adenosine concentration will be measured.

Inclusion Criteria:

• sepsis (according to the criteria of the International Sepsis Definition Conference)

Exclusion Criteria:

• pregnancy
• malignancy
• corticoid therapy
• organ transplantation
• renal insufficiency with HD

Patients with sepsis of pulmonary or abdominal origin with admission to the ICU in the first 48 hours of sepsis onset