The aim of this study is to link defined clinical phenotypes with data on RNA obtained from blood samples by high throughput technologies. Genetic and molecular characteristics of the immune system after severe trauma will be crosslinked to clinical aspects of posttraumatic organ failure, with the goal of identifying typical molecular "fingerprints". Patients with and without sepsis or organ failure will be compared with the goal to develop a diagnostic test designed to predict the clinical course following severe trauma. Criteria for study enrollment includes patient age ≥18 y, an Injury Severity Score (ISS) ≥ 17 points, and time from injury to admission < 6 h. Whole blood from trauma patients will be collected within the first 6 h after trauma (day 0) and on days 1, 2, 3, 5, 7, 10, 14, and 21.