ILT6, also known as CD85e, LIR4, and LILRA3, contains four Ig-like C2-type domains and is the only ILT family member that lacks a transmembrane and cytoplasmic domain. ILT proteins modulate immune responses through interactions with class I MHC molecules. Several polymorphisms of ILT6 have been described, and loss of ILT6 is associated with the development of multiple sclerosis. Human and chimpanzee ILT6 share 84% aa sequence identity. ILT6 orthologs have not been described in other species.