ILT4, also known as LILRB2, is a member of the the subfamily B class of LIR receptors which contain two or four extracellular immunoglobulin domains, a transmembrane domain, and two to four cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs). ILT4 gene is a member of the leukocyte immunoglobulin-like receptor (LIR) family. Multiple transcript variants encoding different isoforms have been found for ILT4 gene. ILT4 is expressed on immune cells where it binds to MHC class I molecules on antigen-presenting cells and transduces a negative signal that inhibits stimulation of an immune response. It is thought to control inflammatory responses and cytotoxicity to help focus the immune response and limit autoreactivity.