In addition to being expressed as a GPI-anchored membrane protein, CD14 is also expressed in a soluble form (sCD14) [2] . sCD14 may result from secretion of the protein before coupling to the GPI anchor or from shedding or cleavage from the surface of monocytes. sCD14 is present in the circulation and other body fl uids and levels of sCD14 in plasma increase during infl ammation and infection. Since interleukin (IL)-6 induces sCD14 expression in liver cells it is regarded as an acute phase protein. In bronchoalveolar lavage (BAL) fl uid from patients with acute respiratory distress syndrome (ARDS), sCD14 levels were strongly increased and correlated with total protein levels and neutrophil numbers in the BAL fl uid [6] , suggesting that sCD14 contributes to the infl ammatory process in the lung.