The CD300 glycoproteins are a family of related leucocyte surface molecules that modulate a broad and diverse array of immune cell processes via their paired activating and inhibitory receptor functions (Clark et al. 2000, 2001, 2009a,b). Human CD300 family include 7 members and they have a single Ig-V like domain. Only CD300a and CD300f have long cytoplasmic tails with ITIMs (immunoreceptor tyrosine-based inhibitory motif), whereas the rest of the members have a short cytoplasmic tail and a short transmembrane residue and associate with adaptor proteins such as DDNAX associated protein (DAP)12, DAP10, and the Fc receptor gamma (FCRG) (Clark et al 2009a, Borrego 2013). CD300 receptors bind to polar lipids including extracellular ceramide, phosphatidylserine, and phosphatidylethanolamine, that are exposed on the outer leaflet of the plasma membrane of dead and activated cells. The CD300 gene complex has been linked to PSOR2, a susceptibility locus for psoriasis (Speckman et al. 2003, Tomfohrde et al. 1994).