During the progression of sepsis from early hit to multiorgan failure proinflammatory and anti-inflammatory cytokines are released. Cytokines can be used as biomarkers to determine the specific patterns of sepsis progression and association with mortality. In our study CRP levels correlated with the probability of survival, following levels of TREM-1, PCT and IL-6. Contrary to CRP and PCT levels, which rapidly fell during the first study days, levels of cytokines and TREM-I remained elevated throughout the study period, but were not so high and even normal in these subjects with severe sepsis despite early enrolment. Severity of disease at presentation correlated with levels of CRP, PCT, TREM-1, IL-6, IL-12, IL-4, IL-1 beta and TNF, especially in children. Response of circulating cytokines in patients with severe sepsis is heterogeneous in adults and children population and there is a specific pattern of this response related to mortality and severity at presentation. Furthermore, this pattern of response is different when comparing paediatric and adult patients.