To address this hypothesis and to study potential underlying mechanisms, we measured levels of leukocyte Aqp1 expression in critically ill patients at ICU admission, upon diagnosis of sepsis and at occurrence of septic shock; in additional in vitro experiments we probed the capacity of lipopolysaccharide (LPS) to regulate Aqp1 expression in polymorphonuclear granulocytes (PMNs) and investigated potential signaling pathways and functions. The gene discussed is AQP1; the disease is Sepsis.