Unexplained or persistent leukocytosis is an increasing common cause of consultation to infectious disease physicians. Patients appear to be in a state of continued inflammation recently described as the Persistent Inflammation-Immunosuppression and Catabolism Syndrome (PICS). Hospital course of such patients is frequently prolonged and associated with extensive use of empiric broad spectrum antibiotics. We wished to determine the associated clinical features and outcome of such patients in anticipation of future specific diagnostic and therapeutic approaches to this syndrome.