The ILT gene family includes up to 11 members in the human. The extracellular portion of all members includes at least two and usually four immuno-globulin domains. ILT-2 through 5 are all inhibitory members having variable numbers of cytoplasmic ITIM domains. ILT family proteins are expressed predominantly on myeloid lineage cells, and some members have been shown to bind classical (HLA-A and -B) and non-classical (HLA-G1, -E and -F) MHC class I molecules. Several nomenclatures exist, giving each member a different ILT, LIR, LILR, CD85 or other designation.