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.