Sepsis is a severe complication which is usually caused by microbial infection,severe burns or trauma and major operations.Patients with sepsis were usually complicated with systemic inflammatory response and multi-organ dysfunction syndrome,which is the leading cause of death in the intensive care units.However,the main immunoregulatory mechanisms underlying severe sepsis remain unclear,and effective methods for monitoring immune status and immunomodulatory strategies need to be investigated.In recent years,the understanding of the mechanism of sepsis has been developed.Clinicians have learned that immune dysfunction took part in the pathophysiological process of sepsis.Therefore,rational monitoring of immune status in patients with severe sepsis after burns or major operation,seeking effective ways for diagnosis,treatment and intervention are of great significance in decreasing the mortality and improving the life quality.