TREM1 and infection: During an infection, the expression of membrane-bound TREM-1 is increased (Gibot and Cravoisy 2004; Gibot et al. 2005) and the level of sTREM-1 is elevated in plasma, bronchoalveolar lavage fluid and spinal fluid (Determann et al. 2006; Jiyong et al. 2009; Oudhuis et al. 2009).