We hypothesized that brain death is associated with an early systemic inflammatory response, possibly combined with activation of apoptotic cell death, two events that may contribute to induce rapid organ dysfunction. In this study of brain-dead donors and controls, we assayed plasma cytokines and soluble factors, investigated plasma endotoxin levels as a triggering factor for inflammation, measured ex vivo cytokine production by blood leukocytes to determine whether immunosuppression occurred after brain death, and examined skeletal muscle biopsies to look for evidence of inflammation and increased apoptosis in peripheral tissue.