Leukocyte-associated Ig-like receptor-1 (LAIR1 or CD305) is a member of the Ig superfamily (IgSF), which is expressed on almost all immune cells, mostly on PBMCs and thymocytes (Meyaard et al. 1997). Collagens are functional ligands for LAIR1 and upon their interaction mediate an inhibitory signal to immune cell activation (Lebbink et al. 2006, Meyaard 2008). An interesting implication of the discovery of LAIR1 as an inhibitory collagen receptor is that tumor cells, known to upregulate collagen expression, may use this interaction to downregulate responses directed against the tumor by various effector cells (Meyaard 2010). Upon cross-linking of the receptor with mAbs, LAIR1 gets phosphorylated on the tyrosine residues in the cytoplasmic ITIMs and recruits SHP1 and SHP2 and C-terminal Src Kinase (Csk) (Verbrugge et al. 2006).