Leukocyte immunoglobulin-like receptor subfamily A member 3 (LILR-A3) also known as CD85 antigen-like family member E (CD85e), immunoglobulin-like transcript 6 (ILT-6), and leukocyte immunoglobulin-like receptor 4 (LIR-4) is a protein that in humans is encoded by the LILRA3gene located within the eukocyte receptor complex on chromosome 19q13.4. Unlike many of its family, LILRA3 lacks a transmembrane domain. The function of LILRA3 is currently unknown. however it is highly homologous to other LILR genes, and can bind human leukocyte antigen (HLA) class I. Therefore, if secreted, the LILRA3 might impair interactions of membrane-bound LILRs (such as LILRB1, an inhibitory receptor expressed on effector and memory CD8 T cells) with their HLA ligands, thus modulating immune reactions and influencing susceptibility to disease.
Like the closely related LILRA1, LILRA3 binds to both normal and 'unfolded' free heavy chains of HLA class I, with a preference for free heavy chains of HLA-C alleles 
^Arm JP, Nwankwo C, Austen KF (Sep 1997). "Molecular identification of a novel family of human Ig superfamily members that possess immunoreceptor tyrosine-based inhibition motifs and homology to the mouse gp49B1 inhibitory receptor". J Immunol159 (5): 2342–9. PMID9278324.
^Borges L, Hsu ML, Fanger N, Kubin M, Cosman D (Apr 1998). "A family of human lymphoid and myeloid Ig-like receptors, some of which bind to MHC class I molecules". J Immunol159 (11): 5192–6. PMID9548455.
^Jones DC, Kosmoliaptsis V, Apps R, Lapaque N, Smith I, Kono A, Chang C, Boyle LH, Taylor CJ, Trowsdale J, Allen RL (Mar 2011). "HLA class I allelic sequence and conformation regulate leukocyte Ig-like receptor binding". J Immunol186 (5): 2990–7. doi:10.4049/jimmunol.1003078. PMID21270408.
Samaridis J, Colonna M (1997). "Cloning of novel immunoglobulin superfamily receptors expressed on human myeloid and lymphoid cells: structural evidence for new stimulatory and inhibitory pathways.". Eur. J. Immunol.27 (3): 660–5. doi:10.1002/eji.1830270313. PMID9079806.
Wiśniewski A, Łuszczek W, Mańczak M et al. (2004). "Distribution of LILRA3 (ILT6/LIR4) deletion in psoriatic patients and healthy controls.". Hum. Immunol.64 (4): 458–61. doi:10.1016/S0198-8859(03)00025-9. PMID12651072.CS1 maint: Explicit use of et al. (link)
Norman PJ, Carey BS, Stephens HA, Vaughan RW (2003). "DNA sequence variation and molecular genotyping of natural killer leukocyte immunoglobulin-like receptor, LILRA3.". Immunogenetics55 (3): 165–71. doi:10.1007/s00251-003-0561-1. PMID12750859.
Rual JF, Venkatesan K, Hao T et al. (2005). "Towards a proteome-scale map of the human protein-protein interaction network.". Nature437 (7062): 1173–8. doi:10.1038/nature04209. PMID16189514.CS1 maint: Explicit use of et al. (link)