Leukocyte-associated immunoglobulin-like receptor 2 ( LAIR2 ), also known as CD306, is a 131 amino acid protein containing one lg-like C2-type domain. It is expressed as a soluble receptor exhibiting high affinity for various collagen molecules to which it binds in a hydroxyproline-dependent manner. LAIR2 is a member of the immunoglobulin superfamily and was identified by its similarity to LAIR1, an inhibitory receptor present on mononuclear leukocytes. LAIR2 is thought to be secreted and may help modulate mucosal tolerance. As a natural competitor for LAIR1, soluble LAIR2 prevents binding of human LAIR1 to collagens and LAIR1 cross-linking, thereby regulating its inhibitory potential. Accordingly, LAIR2 is suggested to perform an immunoregulatory function.